#geometry-and-trigonometry | Mathematics | Page 179

white harness Sep 26, 2018, 12:38 AM

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Yes (black).

upper karma Sep 26, 2018, 12:38 AM

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second if

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https://gyazo.com/99471cc81606e1aac9c6be08f2239d61

Gyazo

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no

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ur first if is the red part

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ur second the red

white harness Sep 26, 2018, 12:40 AM

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No.

upper karma Sep 26, 2018, 12:42 AM

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https://gyazo.com/44904fa41ef222d64287209642f08042

Gyazo

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yes

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actually, x < 0 && y >= 0 is bad (bot left)

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the discontinuos lane should be changed with the continous

white harness Sep 26, 2018, 12:45 AM

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The rendering is reversed. Yes.

upper karma Sep 26, 2018, 12:45 AM

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yes

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on y axe

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YEAH

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I DID

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FFS

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OMGGGGGGGGGGG

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https://gyazo.com/f0b4d0f79b80989f7d6fc79da9c6ab89

Gyazo

▶ Play video

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idk why 225.00002

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uwu

white harness Sep 26, 2018, 12:50 AM

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Rounding mistake (don't panic, you are using float 32bits).

upper karma Sep 26, 2018, 12:50 AM

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https://gyazo.com/b50f038c4f6be035fcbf89ea1f8a5955

Gyazo

▶ Play video

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asjkvgfasljdbvhsdobv

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im

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so

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fckin

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happy

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tomorrow i will try to do on the correct order

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but basically

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is to reverse the sorted list (?)

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yes XD

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it is reversing XD

white harness Sep 26, 2018, 12:55 AM

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Reverse the rendering with (x, -y).

white harness Sep 26, 2018, 1:12 AM

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@upper karma .

upper karma Sep 26, 2018, 1:14 AM

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im resting :P

white harness Sep 26, 2018, 1:14 AM

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Don't forget (x, -y).

upper karma Sep 26, 2018, 1:15 AM

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ye ye

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dont worry :P

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tyvm PP

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^^

hard gale Sep 26, 2018, 6:48 AM

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Dem DAT ordering (it's kinda logical in a computer tho, kek me)

outer ginkgo Sep 26, 2018, 8:45 AM

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Please, help me. I think I've been staring at my paper for so long. TIA 🙆🏻🙏🏻

📎 JPEG_20180926_161604.jpg

elder vale Sep 26, 2018, 12:32 PM

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Whats graphing a boundary line mean again?

glossy dawn Sep 26, 2018, 3:24 PM

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pretty sure it means the > < >= <= thing

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so y >= 3x + 2

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you draw a thicc line on the line 3x +2

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the line itself being the boundary

bright elbow Sep 26, 2018, 5:45 PM

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Is my formula correct?

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Oh shoot mb wrong channel

wraith solstice Sep 27, 2018, 5:01 AM

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i was working with centri acceleration why are the angles equal?

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📎 ucm2.png

keen aspen Sep 27, 2018, 5:09 AM

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Does the v represent velocity?

twin prawn Sep 27, 2018, 3:08 PM

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The angles are equal because the tangent velocity vector is always perpendicular to the position vector

wild hamlet Sep 27, 2018, 9:00 PM

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each arrow is rotated by 90 degrees so their adjoining angle would be the same

echo star Sep 27, 2018, 11:32 PM

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can anyone here help me with my homework?

upper karma Sep 27, 2018, 11:36 PM

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Considering it's a math server, probably

echo star Sep 27, 2018, 11:37 PM

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📎 20180927_190424.jpg

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📎 20180927_190612.jpg

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📎 20180927_192728.jpg

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sooooo number 39.)

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just confusing af

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i asked a previous server and it doesnt make sense how the answer book says its 16

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how did the book get 16

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if its the answer key, it has to be correct right? unless its wrong.... then ive been scammed like 2 hours

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of mai lyfe

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<@&286206848099549185> i need Help~~

drowsy heron Sep 27, 2018, 11:51 PM

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@echo star The solution is correct. Let me explain.

echo star Sep 27, 2018, 11:53 PM

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ok

drowsy heron Sep 27, 2018, 11:53 PM

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From the picture, ABE = EBF

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Therefore, ABF = ABE+ABF = ABF + ABF = 2 * ABE

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But ABF =7b-24, and ABE=2b

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So, (7b-24) = 2 * (2b)

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Did you arrive at this equation?

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@echo star

echo star Sep 27, 2018, 11:55 PM

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something like that

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i think

drowsy heron Sep 27, 2018, 11:55 PM

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What is the value of b?

echo star Sep 27, 2018, 11:56 PM

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📎 2_people.PNG

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u and this other guy is helping

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he said this is the equation

drowsy heron Sep 27, 2018, 11:57 PM

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I think that equation is incorrect.

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Either that, or there’s a miscommunication.

echo star Sep 27, 2018, 11:57 PM

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ok so which equation should i be doing

drowsy heron Sep 27, 2018, 11:57 PM

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Why would we need a not-equals? Sounds more like a miscommunication than a mistake.

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(7b-24) = 2 * (2b)

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Note the “2 *”

echo star Sep 27, 2018, 11:58 PM

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so is it 7b-24=4b?

drowsy heron Sep 27, 2018, 11:58 PM

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Yeah.

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Do you understand how I got this equation?

echo star Sep 27, 2018, 11:59 PM

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not really :c

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whered u get the (2b)

drowsy heron Sep 27, 2018, 11:59 PM

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From the question

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ABE=2b

echo star Sep 27, 2018, 11:59 PM

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then whered u get 2*

drowsy heron Sep 28, 2018, 12:00 AM

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See what I wrote above.

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From the picture, ABE = EBF
Therefore, ABF = ABE+ABF = ABF + ABF = 2 * ABE
But ABF =7b-24, and ABE=2b
So, (7b-24) = 2 * (2b)

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Copied down here.

echo star Sep 28, 2018, 12:01 AM

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ok sooo

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from 7b-24=4b where to go from there

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b=-8 or 8?

drowsy heron Sep 28, 2018, 12:03 AM

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There’s a single solution for b.

echo star Sep 28, 2018, 12:03 AM

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hmmmm

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im confusedd

drowsy heron Sep 28, 2018, 12:04 AM

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So... you’re saying the solutions to the equation are b=-8 and b=8, right?

echo star Sep 28, 2018, 12:04 AM

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one of them

drowsy heron Sep 28, 2018, 12:04 AM

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Well... have you figured out which?

echo star Sep 28, 2018, 12:04 AM

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-8? right

drowsy heron Sep 28, 2018, 12:05 AM

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Just try plugging the numbers in 😅

echo star Sep 28, 2018, 12:05 AM

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8

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ok so 8

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then wat

drowsy heron Sep 28, 2018, 12:07 AM

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Ok. Do you understand how I got the equations?

echo star Sep 28, 2018, 12:07 AM

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yeah i get it

drowsy heron Sep 28, 2018, 12:07 AM

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Oh wait.

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I made a typo in my equation.

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Sorry.

echo star Sep 28, 2018, 12:08 AM

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wat is it

drowsy heron Sep 28, 2018, 12:08 AM

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From the picture, ABE = EBF
Therefore, ABF = ABE+EBF = ABE + ABE = 2 * ABE
But ABF =7b-24, and ABE=2b
So, (7b-24) = 2 * (2b)

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Edited the second line.

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That must have been confusing 😅😑

rose reef Sep 28, 2018, 12:08 AM

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help anyone thanks im a freshman and I’m taking high honors geometry

📎 image0.jpg

echo star Sep 28, 2018, 12:09 AM

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ok so then what thoooo

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i got 8

drowsy heron Sep 28, 2018, 12:10 AM

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@echo star So, now we have the value of b. We want to to find EBF. But we know EBF=ABE. Do you know how to find ABE?

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@rose reef I’d suggest asking in one of the question rooms 😅 sorry.

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@echo star Do you understand?

echo star Sep 28, 2018, 12:10 AM

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trynna comprehend hold up

rose reef Sep 28, 2018, 12:10 AM

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oky

echo star Sep 28, 2018, 12:11 AM

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u plug 8 into the b in 2b?

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wait

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16

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=/

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lol

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ok

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uhhh

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thx man

drowsy heron Sep 28, 2018, 12:11 AM

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Yup.

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:)

echo star Sep 28, 2018, 12:33 AM

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@drowsy heron wait one more thing

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📎 geo.jpg

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with 41 how do u set it up

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i just need that

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nvm nvm

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got it

desert quail Sep 28, 2018, 5:34 AM

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Can someone help me with analytic geometry?

keen aspen Sep 28, 2018, 5:37 AM

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Sure

cold plaza Sep 28, 2018, 5:58 AM

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if you have a circle in the xy plane of the 3 dimensional space. (including z axis)
and plot a height point projecting upward from the midpoint of all pairs of points in the circle. and the height is equal to the distance between the points on the circle.

how would the resultant shape/curve/surface look like?

torn goblet Sep 28, 2018, 6:06 AM

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it'll look like a worm hole

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those boom tubes in justice league unlimited

cold plaza Sep 28, 2018, 6:07 AM

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shit I thought it was a cone

torn goblet Sep 28, 2018, 6:08 AM

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oh damn ur right

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i'm gonna go revaluate my life

cold plaza Sep 28, 2018, 6:08 AM

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daaaamn im smart

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im not 100% sure tho is if any PhDs wanna authoritatively answer, that'd be great

torn goblet Sep 28, 2018, 6:09 AM

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tbh i don't know, i just guessed what came to mind at the time.

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loool

cold plaza Sep 28, 2018, 6:10 AM

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man i thought of a technique to show its a cone

torn goblet Sep 28, 2018, 6:10 AM

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📎 9092F33A-CAA2-4262-BD1B79BC5EF6530E.png

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wormholes are pretty

cold plaza Sep 28, 2018, 6:10 AM

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yeah. i wanna go inside one

tribal wind Sep 28, 2018, 6:11 AM

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📎 Light-cones-in-general-pseudo-Riemannian-space-time-after-Penrose-2007.png

cold plaza Sep 28, 2018, 6:23 AM

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here's a related problem... if you take a fixed point on a circle, and draw lines out to all other points on the circle... and then you connect all the midpoints of all lines... do you get a circle?

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sometimes I wish I was good at art

white harness Sep 28, 2018, 6:39 AM

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Image please.

cold plaza Sep 28, 2018, 6:41 AM

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📎 IMG_2097.JPG

white harness Sep 28, 2018, 6:43 AM

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Yes, the result is a circle.

cold plaza Sep 28, 2018, 6:43 AM

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why

white harness Sep 28, 2018, 6:44 AM

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Homothety.

cold plaza Sep 28, 2018, 6:45 AM

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whoa thats advanced

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could you please verify my question posted at like 40 min ago? the one with xyz

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more like 48 min ago

white harness Sep 28, 2018, 6:49 AM

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It will have a volume.

cold plaza Sep 28, 2018, 6:49 AM

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but the volume of a cone?

white harness Sep 28, 2018, 6:54 AM

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Sorry, it can't have one.

cold plaza Sep 28, 2018, 6:55 AM

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so its just a surface then right. Its the surface of a cone right?

errant ether Sep 28, 2018, 7:04 AM

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I don't think it can be a cone. Consider the curve drawn out by taking the midpoints of a set of parallel chords down the circle. The midpoints form a straight line in the xy plane and I believe a semicircle in 3d space, which doesn't lie entirely on a cone. In fact I'd guess the surface is a hemisphere but I'm not really sure

cold plaza Sep 28, 2018, 7:06 AM

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hmm maybe come up with a function of the distance between the end points of the parallel chords... then we apply calculus to see if its changing linearly or not

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that would help

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for a unit circle centered in the origin (polar coordinates) the height of each parallel chord that's parallel to the y axis is 2 sin(theta)

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so yeah... i guess this shows it cant be a cone? because the slant of the cone increases linearly right?

errant ether Sep 28, 2018, 7:11 AM

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yeah the gradient of a function describing a cone is linear

cold plaza Sep 28, 2018, 7:11 AM

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knew there was something wrong with my cone hypothesis

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wait acutally

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shouldn't I be finding the function in rectangular coordinates instead?

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because varying theta isn't like, uh, smoothly going across the x axis

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and what I want to analyse is how the height changes as I smoothly go across the x axis

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fuck I have like boring math homework but this shit is just pulling me in

errant ether Sep 28, 2018, 7:15 AM

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I went about it by considering displacement from the diameter

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A chord parallel to and at a displacement x from a diameter forms a right triangle with the radius from its end on the circle to the center of the circle, the line from its center to the center of the circle, and half its own length. Half its own length is also the length to its midpoint from its end, we'll call it h. Then h^2 + x^2 = r^2, where h = z is the height, so we have a circle in the xz plane (or semicircle over the bounds of x). Consider the set of all sets of parallel chords as the rotation of a set of parallel chords. A set of parallel chords draws out a semicircle and a rotation of semicircles forms a hemisphere.

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Now this could be complete nonsense, not sure lol

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📎 chordthing.png

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where blue is some random chord and red is a diameter

cold plaza Sep 28, 2018, 7:20 AM

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yeah no im still processing the " hence we have a semicircle in the xz plane" part

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my visualization skills are pathetic

errant ether Sep 28, 2018, 7:22 AM

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gotcha, it's difficult to wrap your head around this a lot of the time lol

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assuming again of course I'm not making it more difficult by being nonsensical

cold plaza Sep 28, 2018, 7:27 AM

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yeah this is kinda what I was saying (about a function with rectangluar coordinates)

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ok so correct me if I'm wrong

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but x^2 + h^2 = r^2

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dh/dx = - (x/h) = - (x/ sqrt(r^2 - x^2))

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so since h changes non-linearly with respect to x

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its not a cone

errant ether Sep 28, 2018, 7:28 AM

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yep

cold plaza Sep 28, 2018, 7:31 AM

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yeah I like your proof

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makes sense to me

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honestly I was inspired of asking all this due to a 3Blue1Brown video

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O_O

errant ether Sep 28, 2018, 7:33 AM

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not a bad place to be inspired lol I should watch more of his vids myself

cold plaza Sep 28, 2018, 7:35 AM

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yeah I was searching for like some meaning/purpose behind all these advanced mathematical definitions and their implications.. I seem to have gotten it back now. MAYBE TOPOLOGY ISN'T A COMPLETE WASE OF TIME

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just maybe

errant ether Sep 28, 2018, 7:36 AM

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lol

white harness Sep 28, 2018, 11:30 AM

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Assuming the radius is one.

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$$
h = x\tan(\arccos(x))
$$.

charred spearBOT Sep 28, 2018, 11:31 AM

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📎 latex.png

unique tulip Sep 28, 2018, 7:20 PM

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📎 image0.jpg

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Someone helppppop

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😢

umbral snow Sep 28, 2018, 7:28 PM

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@unique tulip
What's the x and y intercept of 2x + 3y - 13 = 0?

crystal edge Sep 28, 2018, 11:00 PM

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Hello!
I have this and know it works

So I want to a point along a vector. I have (x0,y0) to (x1,y1)
Distance is SQRT( SQ(x0-x1)+SQ(y0-y1))
Basic Trig. 
So if I want to find a point distance Q along this line I get
Ratio = Q/d
Then I use that to find point using
xn = (1-ratio)x0 + x1*ratio
Same for y.

How does this work? I did take vector geometry so I should know, just need a refresher ie. Don't go too much in detail.

cunning mist Sep 29, 2018, 12:43 AM

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Hi, is there a way to know that a face of a polygon is pointing in the wrong direction? (inward a surface)

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I have some polygons displaying correctly and some flipped

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I need to matematically invert the flipped faces

white harness Sep 29, 2018, 12:44 AM

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Cross product.

cunning mist Sep 29, 2018, 12:44 AM

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how would I use the cross product?

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📎 unknown.png

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the blue part is facing inward

white harness Sep 29, 2018, 12:46 AM

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Let A, B, C be your points. Then $$\overrightarrow{AB}\wedge\overrightarrow{AC}$$ is a vector.

charred spearBOT Sep 29, 2018, 12:46 AM

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📎 latex.png

white harness Sep 29, 2018, 12:47 AM

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OpenGL ?

cunning mist Sep 29, 2018, 12:48 AM

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Unity, but the problem is that my mesh is converted from step (catia) to polygon using open cascade~

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I can't fix it manually

white harness Sep 29, 2018, 12:48 AM

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Is it only the blue part ?

cunning mist Sep 29, 2018, 12:49 AM

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this problem occurs sometimes only

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the blue part is only an example

white harness Sep 29, 2018, 12:51 AM

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You can choose a point inside the object. Compute the cross product then compute the dot product if the sign is positive then change points otherwise leave it unchanged.

cunning mist Sep 29, 2018, 12:51 AM

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a point inside the object? like the center of the bounding box?

white harness Sep 29, 2018, 12:51 AM

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Yes.

cunning mist Sep 29, 2018, 12:52 AM

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would that work for a non convex mesh?

white harness Sep 29, 2018, 12:52 AM

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No.

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The best solution is to generate the right mesh.

cunning mist Sep 29, 2018, 12:54 AM

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yes

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that's the problem hehe

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I could also convert a non convex mesh to a sequence of convex meshes

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and then do what you suggested before

white harness Sep 29, 2018, 12:58 AM

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Another way to fix it is to have one good vector toward the outside and then by recursion check the neighbours. But the non-convexity problem remains.

cunning mist Sep 29, 2018, 1:01 AM

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thanks anyway

white harness Sep 29, 2018, 1:02 AM

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You are welcome.

cunning mist Sep 29, 2018, 1:02 AM

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do you have any idea how physX checks for collisions of non convex meshes?

white harness Sep 29, 2018, 1:03 AM

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No idea.

cunning mist Sep 29, 2018, 1:03 AM

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that could do the trick hehe

wild hamlet Sep 29, 2018, 5:12 PM

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That moment when the teacher says abs(sin(x))<=1 for all x

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:)

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you woulda thout srub

zenith cobalt Sep 29, 2018, 6:37 PM

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Pretty simple question, but I was never taught ellipses in hs :/

need the y coords of intersections of these two intersecting ellipses: https://www.desmos.com/calculator/xpuzpxcdzs

after some manipulation I get y^2+8y+8 = 0

which gives x = -1.172 and x = -6.828

I can clearly see how the -1.172 fits in, but what does the -6.828 represent?

Desmos Graphing Calculator

Differential Calculus Assignment No. 1

wild hamlet Sep 29, 2018, 6:47 PM

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would that 6.828 be 4+2sqrt(2)?

zenith cobalt Sep 29, 2018, 6:50 PM

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the quadratic equals -4+2sqrt(2) and -4-2sqrt(2). I'm kinda just wondering how the single x = -1.172 translates to the y of both intersections, and the -6.828 equals nothing 🤔

unique tulip Sep 30, 2018, 5:48 PM

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@umbral snow y intercept = to when x is O so put that in and then x intercept = to when y is o so put that in, and then u get x and y intercept, the question is tricky n idk how to do it. Isosceles triangle has to have 2 sides that r the same

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Thank you 👍💚 @Mr. L#3864

lone sundial Oct 1, 2018, 1:04 AM

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Hi

echo star Oct 1, 2018, 10:16 PM

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📎 20181001_181538.jpg

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📎 20181001_181545.jpg

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can i get help with number 3

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im so confused

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i get the terms and all but im confused

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the squares means angle (the computer made it like that idk why) and on number 3, the angle is FGC, its cut off

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Adjacent- 2 angles that share the same vertex

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Complementary- equal to 90 degrees

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Plz helppppp

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ok nvm

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got it

errant ether Oct 2, 2018, 12:42 AM

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It's March on March 2nd but it's not st patrick's, is the statement true or false there?

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why?

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to be clear I'm asking about the statement "If it is March, it is St. Patrick's Day."

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not the statement I made

amber raven Oct 2, 2018, 12:46 AM

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That's false

upper karma Oct 2, 2018, 12:49 AM

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quick basic geometry question: arent all postulates/axioms considered to have a 100% truth value?

tribal wind Oct 2, 2018, 12:50 AM

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ye

upper karma Oct 2, 2018, 12:51 AM

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"If it is March, it is St. Patrick's Day." Truth Value: False | Statement Type: Converse

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oops

amber raven Oct 2, 2018, 12:51 AM

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@upper karma if it's an axiom you have chosen to work with

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And also does not lead to contradictions which the other axioms you have chosen to work with

upper karma Oct 2, 2018, 12:55 AM

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"If it is March, it is St. Patrick's Day." Truth Value: True | Statement Type: Converse
If it is St. Patrick's Day, "It is March" Truth Value: True | Statement Type: Conditional
If it is not St. Patricks Day, it is not March" Truth Value: True | statement type: Inverse
If it is not March, then it is not St. Patricks Day" Truth Value: True | statement type: Contrapositive

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wouldnt it be this @upper karma

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?

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but make sure it is true for all

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becuz if conditional is true than converse must be too

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oh yea my bad

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im a little stumped on that too

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i understand your logic but the converse statement is a bit tedious

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it should be false for all i think

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but then the contrapositive is true tho...hmmmmm

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yea that conditional is weird

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well if contrapositive is true, then the conditional statement must also be true

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yes, same goes with converse and inverse

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you cannot have 1 or 3 true statements

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you can only have 0, 2 or 4

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np

upper karma Oct 2, 2018, 2:01 AM

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Is topology ever discussed here

amber raven Oct 2, 2018, 2:23 AM

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Ue

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Yes

upper karma Oct 2, 2018, 2:24 AM

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Hm

silver wolf Oct 2, 2018, 6:10 AM

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Im looking for help on how to do angles like vertical congruent supplementary and complementary

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<@&286206848099549185>

amber raven Oct 2, 2018, 12:49 PM

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@silver wolf vertical angles idk.
Congruent angles are a pair of angles that can be moved or rotated on to each other so that they cover the exact same space. Congruent means the same. Congruent angles are equal. The only difference between two congruent angles is where they are located and oriented in the plane.

Summplementary angles add up to 180

Complimentary angles add up to 90

What I mean by add up is but the sides of the angles together to you will get a new angle formed by the opposite of sides

upper karma Oct 2, 2018, 12:59 PM

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📎 IMG20181002204335.jpg

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Hello. How do I do this?

pulsar merlin Oct 2, 2018, 1:46 PM

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Oh sorry use similar triangles

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@upper karma

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Triangles are given in pairs

upper karma Oct 2, 2018, 1:46 PM

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similar triangles?

pulsar merlin Oct 2, 2018, 1:48 PM

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Prove triangle are similar AAA test in first one

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He needs to state by which test the triangles are similar before solving them

mild cargo Oct 2, 2018, 1:50 PM

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Similar triangles have equal correspondong angles and equal ratio of corresponding sides

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But you can't use it until you show they are similar

upper karma Oct 2, 2018, 1:52 PM

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Sorry but what is the 1st step?

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my brain is overloaded

pulsar merlin Oct 2, 2018, 1:53 PM

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Prove these are similar triangles

upper karma Oct 2, 2018, 1:53 PM

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how do i prove it??

pulsar merlin Oct 2, 2018, 1:53 PM

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https://topdrawer.aamt.edu.au/Geometric-reasoning/Big-ideas/Similarity/Similar-triangles

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Read it

twin prawn Oct 2, 2018, 1:54 PM

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I can assure you most people on here would Google if they could

pulsar merlin Oct 2, 2018, 1:55 PM

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I can teach him how to apply test of similarity, but if he doesn't know the test, how can I proceed ?

upper karma Oct 2, 2018, 3:30 PM

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I gave up

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My maths teacher teaches 3 topics a day in an hour. How am i supposed to catch up?

elfin mica Oct 2, 2018, 3:56 PM

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does anyone know how to find the volume of a truncated sqaure pyramid using similar triangles?

elfin mica Oct 2, 2018, 4:22 PM

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<@&286206848099549185>

wild hamlet Oct 2, 2018, 8:54 PM

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truncated square pyramid...

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im guessing the volume of the full pyramid minus the volume of the cut off pyramid

quiet bolt Oct 2, 2018, 9:47 PM

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I have a very important question

keen aspen Oct 2, 2018, 9:48 PM

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ya'

upper karma Oct 3, 2018, 12:42 AM

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Wait wait

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Where is topology

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😦

plain wigeon Oct 3, 2018, 12:51 AM

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#point-set-topology

upper karma Oct 3, 2018, 12:52 AM

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👍

little osprey Oct 3, 2018, 1:33 PM

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In the acute triangle ABC, D is on AB, E is on AC, and the points F and G are on BC (F is closer to B).
If : DB = DF = DE = AE = EC = CG = FG
Find the angles of ABC.

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📎 unknown.png

little osprey Oct 3, 2018, 1:51 PM

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<@&286206848099549185>

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Looks like I'm oofed.

solid orchid Oct 3, 2018, 1:55 PM

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I'm no math expert, but you should be able to conclude that if DF and DB are equal in length, the angle of B and F needs to be the same right?

little osprey Oct 3, 2018, 1:57 PM

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Which angle of F.

solid orchid Oct 3, 2018, 1:57 PM

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the left

little osprey Oct 3, 2018, 1:57 PM

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Yes.

solid orchid Oct 3, 2018, 1:57 PM

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AC = 2a
BC = 2a + ?
AB = a + ?
might be useful to solve for the unknown

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you might be able to with the Pythagorean theorem

little osprey Oct 3, 2018, 1:58 PM

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Uhh

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I'm trying to find angles.

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And no.

solid orchid Oct 3, 2018, 1:58 PM

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if you know the lengths of the three sides, shouldn't you be able to determine the angles?

little osprey Oct 3, 2018, 1:58 PM

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Pythagorean Theorem is not possible.

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Yeah if it's equilateral.

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Which it maybe.

solid orchid Oct 3, 2018, 1:59 PM

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https://www.mathsisfun.com/algebra/trig-solving-sss-triangles.html

little osprey Oct 3, 2018, 2:00 PM

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There is no way to get BF.

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Ok, I'll be back later on.

solid orchid Oct 3, 2018, 2:01 PM

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is DE parallel to BC?

shadow anvil Oct 3, 2018, 2:02 PM

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Maybe

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You can't assume it is though

solid orchid Oct 3, 2018, 2:02 PM

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DF should be parallel to EC though right

shadow anvil Oct 3, 2018, 2:03 PM

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no

solid orchid Oct 3, 2018, 2:03 PM

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or actually maybe not

little osprey Oct 3, 2018, 2:13 PM

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Ok, I'm back.

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@solid orchid DF is parrallel to EG

solid orchid Oct 3, 2018, 2:13 PM

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is that even possible?

little osprey Oct 3, 2018, 2:14 PM

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Use similar triangles

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afc and egc are similar

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then you can prove parallel lines by corresponding angles being the same.

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You understand what I did?

solid orchid Oct 3, 2018, 2:15 PM

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doesn't that just mean AF is parallel to EG

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I don't have any expertise in geometry, mind you

little osprey Oct 3, 2018, 2:16 PM

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Oh yes.

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My apologies.

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Not DF

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My mind isn't at it's best state.

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I'm not an expert either.

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But I do what I can.

solid orchid Oct 3, 2018, 2:17 PM

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does geogebra allow unknown lengths or something? Seems like a computer aided tool would be perfect for problems like this

little osprey Oct 3, 2018, 2:18 PM

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hm....

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I don't know.

solid orchid Oct 3, 2018, 2:19 PM

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I should probably make one if there are none already

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seems like it would be super handy

little osprey Oct 3, 2018, 2:20 PM

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But I mean.

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I kinda want to solve it.

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With proof and everything.

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Eh.

solid orchid Oct 3, 2018, 2:21 PM

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the computer would give a reason lol

little osprey Oct 3, 2018, 2:21 PM

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Geogebra doesn't give reasoning?

solid orchid Oct 3, 2018, 2:21 PM

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but yea, solving by hand can be more satisfying

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but when you're stuck, computer aid can be nice

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it can help expand knowledge as well

little osprey Oct 3, 2018, 2:22 PM

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true.

solid orchid Oct 3, 2018, 2:41 PM

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from playing around with http://geometryexpressions.com/gxweb/
it looks like F might be equal to B

GXWeb

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not sure if that's possible by the definition given

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this might be how it looks

📎 unknown.png

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where F and B are on the same location

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which would make the triangle equilateral

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I'm pretty sure it follows the same rules you gave

chilly notch Oct 3, 2018, 8:04 PM

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📎 unknown.png

waxen gorge Oct 3, 2018, 8:04 PM

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So

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we have two quarter circles

chilly notch Oct 3, 2018, 8:05 PM

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yeah

waxen gorge Oct 3, 2018, 8:05 PM

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Or radius 10

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of

chilly notch Oct 3, 2018, 8:05 PM

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area of those are 25pi each

waxen gorge Oct 3, 2018, 8:05 PM

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yes

chilly notch Oct 3, 2018, 8:07 PM

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i got that and that but i'm stuck from therer

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*there

waxen gorge Oct 3, 2018, 8:07 PM

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lemme think

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Well we know the height from the bottom to the top intersection is 5sqrt3

chilly notch Oct 3, 2018, 8:13 PM

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erm...

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hold on

waxen gorge Oct 3, 2018, 8:13 PM

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@chilly notch what class r u taking

chilly notch Oct 3, 2018, 8:13 PM

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year 9

waxen gorge Oct 3, 2018, 8:13 PM

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Like is this only with geometry or can u use calculus

chilly notch Oct 3, 2018, 8:13 PM

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this is only with geometry

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i have one of those teachers who doesn't like using advanced methods for simple questions

waxen gorge Oct 3, 2018, 8:16 PM

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I feel like there's a super easy way to do it but I'm dumb

chilly notch Oct 3, 2018, 8:16 PM

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same

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argh

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i'm sure nobody else in my class will get it though

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only that one guy who is a genius

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and took a-levels when he was 5

waxen gorge Oct 3, 2018, 8:17 PM

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What are a-levels

upper karma Oct 3, 2018, 8:17 PM

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t!wiki a-levels

loud cedarBOT Oct 3, 2018, 8:17 PM

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📖 | ** https://en.wikipedia.org/wiki/Level **

Level

Level or levels or may refer to:

waxen gorge Oct 3, 2018, 8:17 PM

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R u a British pleb

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European

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Idk

chilly notch Oct 3, 2018, 8:17 PM

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yes i'm a british pleb

waxen gorge Oct 3, 2018, 8:17 PM

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owo

chilly notch Oct 3, 2018, 8:20 PM

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📎 Sketch.png

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well boys, my time is up

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*and girls

waxen gorge Oct 3, 2018, 8:23 PM

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The diagonal is 10

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It's 30,60,90

chilly notch Oct 3, 2018, 8:25 PM

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how do you know though

clear haven Oct 3, 2018, 8:26 PM

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it was equilateral

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then he split it in half

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so 306099

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306090*

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thus 10 for hypotenuse

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idk how that helps tho but ye

waxen gorge Oct 3, 2018, 8:27 PM

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He put a ? Next to the diagonal

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So

clear haven Oct 3, 2018, 8:27 PM

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o ok

waxen gorge Oct 3, 2018, 8:28 PM

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@chilly notch did u make that or find it online

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<@&286206848099549185> ?

tribal wind Oct 3, 2018, 8:35 PM

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36

waxen gorge Oct 3, 2018, 8:37 PM

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@tribal wind how owo

tribal wind Oct 3, 2018, 8:37 PM

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idk any geometry

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just use formula for circle

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like sqrt(100-x^2)

clear haven Oct 3, 2018, 8:38 PM

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thonker

waxen gorge Oct 3, 2018, 8:40 PM

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ya but how does that prove all the sides are 6 like

tribal wind Oct 3, 2018, 8:41 PM

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like one of those circle curves has the equation y=sqrt(100-x^2)

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and for a square you want the height y to equal the width 2|x-1/2|

timber hinge Oct 3, 2018, 8:41 PM

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📎 Screen_Shot_2018-10-03_at_21.41.20.png

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Its pretty obvious from that its 36

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But hardly an elegant method

waxen gorge Oct 3, 2018, 8:42 PM

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like

tribal wind Oct 3, 2018, 8:42 PM

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ur face is elegant

timber hinge Oct 3, 2018, 8:42 PM

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❤

clear haven Oct 3, 2018, 8:42 PM

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oh i see but how is that legit ya

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proof

waxen gorge Oct 3, 2018, 8:42 PM

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I would just maximize it but this is just geometry

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;-;

tribal wind Oct 3, 2018, 8:42 PM

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gl finding the secret hidden line and the rotation

timber hinge Oct 3, 2018, 8:42 PM

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You can prove those points lie on it exactly if you wanna be pedantic but like they do lmao

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📎 Screen_Shot_2018-10-03_at_21.43.03.png

clear haven Oct 3, 2018, 8:43 PM

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yeah

timber hinge Oct 3, 2018, 8:43 PM

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QED

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rEEEEEEEE

waxen gorge Oct 3, 2018, 8:43 PM

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Lol

clear haven Oct 3, 2018, 8:43 PM

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nice proof lol

timber hinge Oct 3, 2018, 8:43 PM

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ikr

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defo didn't steal it

clear haven Oct 3, 2018, 8:43 PM

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mhm

timber hinge Oct 3, 2018, 8:43 PM

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❤

tribal wind Oct 3, 2018, 8:43 PM

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another proof is that since you could draw a right triangle there, it has to be 3-4-5

clear haven Oct 3, 2018, 8:43 PM

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🖤

tribal wind Oct 3, 2018, 8:43 PM

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and it looks too big to have side length 8

timber hinge Oct 3, 2018, 8:44 PM

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~~Or you can use a ruler~~ QED

waxen gorge Oct 3, 2018, 8:44 PM

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why r the numbers so nice ;-;

timber hinge Oct 3, 2018, 8:44 PM

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They pretty much always are in these type of problems

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No calcs and stuff

tribal wind Oct 3, 2018, 8:45 PM

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oh I found the right geometry way to do it

timber hinge Oct 3, 2018, 8:45 PM

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Its more about the method than the actual rote calculations

tribal wind Oct 3, 2018, 8:45 PM

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use the right triangle at the corner of the green square

clear haven Oct 3, 2018, 8:45 PM

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there are a lot of triangles that can be made my fren

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which one

tribal wind Oct 3, 2018, 8:46 PM

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corner of green, corner of 10x10

clear haven Oct 3, 2018, 8:46 PM

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im being dumb but i legit wanna know uwu ty

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yes

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aight

waxen gorge Oct 3, 2018, 8:46 PM

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I'm still confused I cri

tribal wind Oct 3, 2018, 8:47 PM

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so for every geometry problem you have to find the hidden line

clear haven Oct 3, 2018, 8:48 PM

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OH SHIT

tribal wind Oct 3, 2018, 8:48 PM

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📎 unknown.png

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we did it

clear haven Oct 3, 2018, 8:48 PM

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THATS IT

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YEAH ITS HALF

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er wait

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wht

tribal wind Oct 3, 2018, 8:48 PM

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fight me

clear haven Oct 3, 2018, 8:48 PM

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yeah i was thinking that line but what do we do

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angle ?

waxen gorge Oct 3, 2018, 8:49 PM

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wat about the line

tribal wind Oct 3, 2018, 8:49 PM

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make a bunch of variables and solve the same equation you get from using the circle equation xd

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red line is 10, bottom side is (10-x)/2

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height is x

waxen gorge Oct 3, 2018, 8:50 PM

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But how do u find the part of the line not on the square knowing the lines length is 10

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Oh

clear haven Oct 3, 2018, 8:51 PM

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wut y is bottom (10-x)/2

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doesnt that just give you the white bit?

tribal wind Oct 3, 2018, 8:52 PM

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oh

clear haven Oct 3, 2018, 8:52 PM

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shouldnt we add x to that to make it include the green part?

tribal wind Oct 3, 2018, 8:52 PM

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10-(10-x)/2

clear haven Oct 3, 2018, 8:56 PM

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???

torn linden Oct 4, 2018, 12:03 AM

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how do you prove this?

📎 2018-10-03_2.png

high pelican Oct 4, 2018, 12:04 AM

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"D bisects angle BDF"

torn linden Oct 4, 2018, 12:05 AM

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I know

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I need help starting the proof

high pelican Oct 4, 2018, 12:06 AM

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what does it mean for DH to bisect BDF

torn linden Oct 4, 2018, 12:06 AM

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the angle is cut in half

high pelican Oct 4, 2018, 12:07 AM

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or, in other words...

torn linden Oct 4, 2018, 12:07 AM

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Ummm...

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Angle is half? Idk

high pelican Oct 4, 2018, 12:07 AM

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"bisects" means that two things are equal

torn linden Oct 4, 2018, 12:08 AM

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Oh

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So it would be something like:

#

Given:

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Angle 1 = Angle 2

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DH bisects angle BDF

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Therefore BDH = FDH

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is that right?

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do I need more? Am I missing something?

high pelican Oct 4, 2018, 12:10 AM

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yeah

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it could be that the problem is messed up

torn linden Oct 4, 2018, 12:10 AM

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I feel like there's more lol

high pelican Oct 4, 2018, 12:10 AM

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and they wanted DBH = DFH

torn linden Oct 4, 2018, 12:10 AM

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Oh sorry

high pelican Oct 4, 2018, 12:11 AM

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that would be the more natural problem to ask

torn linden Oct 4, 2018, 12:11 AM

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Maybe I have to use one of the postulates or something

high pelican Oct 4, 2018, 12:11 AM

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given what is printed, it really is a one step proof

torn linden Oct 4, 2018, 12:11 AM

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Oh ok

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I got 2 more questions lol

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📎 2018-10-03_3.jpg

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How would I start?

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I really struggle with starting

high pelican Oct 4, 2018, 12:17 AM

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so, what tools do you have for proving triangles congruent?

torn linden Oct 4, 2018, 12:18 AM

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Ok so I got a bunch of postulates and theorems I can use

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Side-Side-Side Postulate

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Side-Angle-Side Postulate

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Angle-Side-Angle Postulate

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Angle-Angle-Side Theorem

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I can use those

high pelican Oct 4, 2018, 12:18 AM

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okay

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which things can you say are equal in the diagram?

torn linden Oct 4, 2018, 12:19 AM

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Um

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Ok well we know that a side and an angle are congruent on both triangles

high pelican Oct 4, 2018, 12:20 AM

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which ones?

torn linden Oct 4, 2018, 12:20 AM

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And that CM is equal to DM

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sooo...

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is it Angle-Angle-Side Theorem?

high pelican Oct 4, 2018, 12:22 AM

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so you have CM = DM, and angle M = angle B

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what information have you not used yet?

torn linden Oct 4, 2018, 12:22 AM

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M is midpoint of AB

high pelican Oct 4, 2018, 12:23 AM

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yes

torn linden Oct 4, 2018, 12:23 AM

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uh..

high pelican Oct 4, 2018, 12:24 AM

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that tells you that two things are equal

torn linden Oct 4, 2018, 12:24 AM

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Which two?

high pelican Oct 4, 2018, 12:25 AM

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If M is in the middle of AB, then...

torn linden Oct 4, 2018, 12:26 AM

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Then AM and MB are equal

high pelican Oct 4, 2018, 12:26 AM

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exactly

torn linden Oct 4, 2018, 12:26 AM

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Ooooh

#

ok

#

Lemme get this

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Wow thanks @high pelican you are great lol

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Or I just have bad logik

high pelican Oct 4, 2018, 12:27 AM

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no problem 😄

torn linden Oct 4, 2018, 12:27 AM

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I got one more one sec thi

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tho

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Ok last one

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📎 2018-10-03.jpg

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So the question here is:

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Can you prove the pairs of triangles are congruent? Justify your answer. If there is not enough information, list what else you would need to know in order to prove they are congruent.

high pelican Oct 4, 2018, 12:36 AM

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so, it looks like we have two sides that we know are equal, and one angle

torn linden Oct 4, 2018, 12:36 AM

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right

high pelican Oct 4, 2018, 12:36 AM

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has there been any discussion about SSA?

torn linden Oct 4, 2018, 12:36 AM

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No...

high pelican Oct 4, 2018, 12:36 AM

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hmm

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well, side-side-angle is missing from your list of theorems

torn linden Oct 4, 2018, 12:37 AM

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Umm apparently ssa isnt a thing...

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https://www.google.com/search?q=ssa+theorem&rlz=1C1CHZL_enUS752US752&oq=ssa+theorem&aqs=chrome..69i57.2213j0j7&sourceid=chrome&ie=UTF-8

high pelican Oct 4, 2018, 12:37 AM

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right

torn linden Oct 4, 2018, 12:37 AM

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Yeah we talked about how SSA isn't a thing in class

high pelican Oct 4, 2018, 12:37 AM

#

okay

#

did they go over an example of when it does not work?

torn linden Oct 4, 2018, 12:38 AM

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Also how ASS isn't a thing either

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um no

high pelican Oct 4, 2018, 12:38 AM

#

hmm

torn linden Oct 4, 2018, 12:38 AM

#

Wait

#

I think I may have something

high pelican Oct 4, 2018, 12:38 AM

#

so that picture makes it look like those two triangles are congruent

#

can you maybe redraw the picture so that the angles and sides are still the same, but the triangles are clearly not congruent?

torn linden Oct 4, 2018, 12:39 AM

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Wait one second

high pelican Oct 4, 2018, 12:39 AM

#

okay

torn linden Oct 4, 2018, 12:41 AM

#

📎 2018-10-03_5.jpg

#

📎 2018-10-03_4.jpg

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Ok so we did this in class

#

Maybe this will help?

#

I can type it out...

high pelican Oct 4, 2018, 12:42 AM

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nah

torn linden Oct 4, 2018, 12:42 AM

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Ok

high pelican Oct 4, 2018, 12:43 AM

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so here's the thing

torn linden Oct 4, 2018, 12:43 AM

#

Ok

high pelican Oct 4, 2018, 12:43 AM

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we have the length of AD fixed, but not the angle DAC

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so imagine AD as a swinging rod that we can move back and forth

torn linden Oct 4, 2018, 12:44 AM

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Ok

high pelican Oct 4, 2018, 12:44 AM

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if we swing AD clockwise, we will eventually reach a point where we touch the bottom line again

torn linden Oct 4, 2018, 12:45 AM

#

Ok

#

Right

#

We will have covered a portion of the entire shape by then

high pelican Oct 4, 2018, 12:45 AM

#

so we would still have those two sides and two angles equal, but now the two triangles are clearly not equal

#

because one is obtuse and one is acute

torn linden Oct 4, 2018, 12:46 AM

#

Ok

high pelican Oct 4, 2018, 12:46 AM

#

so to answer this question, it would help to draw a picture showing the two possibilities for AD

torn linden Oct 4, 2018, 12:47 AM

#

How would I explain it then?

#

Oh another thing

#

The Image is not to scale

#

Or accurate

#

It's just there for help

high pelican Oct 4, 2018, 12:49 AM

#

so if you have two different placements for D, that gives you two noncongruent possibilities for the lower left triangle, and only one of those is congruent to the upper right triangle

#

so we can't say that they are congruent

torn linden Oct 4, 2018, 12:52 AM

#

Remember the question is

#

Can you prove the pairs of triangles are congruent? Justify your answer. If there is not enough information, list what else you would need to know in order to prove they are congruent.

high pelican Oct 4, 2018, 12:52 AM

#

right, and the answer is no

torn linden Oct 4, 2018, 12:52 AM

#

So we can't say they are congruent

#

What would we need to prove that they are congruent

high pelican Oct 4, 2018, 12:52 AM

#

there are a lot of things

torn linden Oct 4, 2018, 12:52 AM

#

Such as?

high pelican Oct 4, 2018, 12:52 AM

#

another equality of sides, another equality of angles

torn linden Oct 4, 2018, 12:52 AM

#

Right

#

That's what I put for the other questions

high pelican Oct 4, 2018, 12:53 AM

#

or even just them both being acute

torn linden Oct 4, 2018, 12:53 AM

#

Again not to scale lol

#

But ok

#

No, because we don't have enough information. To prove they are congruent, we would need to know if angle D and angle B are congruent

#

Or if DC and AB are congruent or not

#

Would that be correct?

high pelican Oct 4, 2018, 12:58 AM

#

looks good, although I would also include a diagram showing how you can make more than one triangle with the same SSA

torn linden Oct 4, 2018, 12:59 AM

#

Ok

#

Thank you!

#

Is there a way to tell someone to rank you up?

high pelican Oct 4, 2018, 1:00 AM

#

I don't really know the procedures 😄

normal vault Oct 4, 2018, 2:03 AM

#

http://farside.ph.utexas.edu/Books/Euclid/Elements.pdf

#

i found the elements

upper karma Oct 4, 2018, 5:25 PM

#

Non Euclidean geom3 also here?

twin prawn Oct 4, 2018, 7:24 PM

#

#geometry-and-manifolds

tiny grail Oct 4, 2018, 9:55 PM

#

some help pls

#

📎 Screen_Shot_2018-10-04_at_10.55.22_pm.png

tiny grail Oct 5, 2018, 4:01 PM

#

any hints anyone ? <@&286206848099549185>

halcyon sierra Oct 5, 2018, 11:24 PM

#

is this amc

upper karma Oct 5, 2018, 11:40 PM

#

this question is gross

tiny grail Oct 6, 2018, 12:12 AM

#

No lol it’s from a tst

rustic cairn Oct 8, 2018, 2:21 AM

#

Are D and C collinear?

📎 image0.jpg

upper karma Oct 8, 2018, 2:50 AM

#

any 2 points are collinear

upper karma Oct 8, 2018, 10:21 AM

#

yeah

upper karma Oct 8, 2018, 7:08 PM

#

📎 unknown.png

tiny grail Oct 8, 2018, 7:09 PM

#

assuming caf and bae are collinear

#

just use adjacent angles on st line add up to 180ºc

upper karma Oct 8, 2018, 7:10 PM

#

My first answer is <CAD and <EAD are adjacent because they share line AD.

tiny grail Oct 8, 2018, 7:13 PM

#

convince urself that CAB is 65º

#

then DAE is 180-65-70

#

@upper karma

upper karma Oct 8, 2018, 7:15 PM

#

📎 unknown.png

#

?

#

@tiny grail

tiny grail Oct 8, 2018, 7:28 PM

#

sorry i didn't really understand the question

upper karma Oct 8, 2018, 7:29 PM

#

Oh, well I kind of understand it but not well, its asking to make three conclusions, that you know to be true about the figure from looking at it, then support your conclusions with postulates or definitions.

#

<@&286206848099549185>

tiny grail Oct 8, 2018, 7:36 PM

#

i think it simply means that if two angles share a common line, then they are next to each other, ie adjacent

upper karma Oct 8, 2018, 7:40 PM

#

Well, everything not bold was my answer to the bolded question.

eager burrow Oct 9, 2018, 2:42 AM

#

hi

#

Did the helper come to

#

anyone here

#

I just need someone point me in a direction

fair wigeon Oct 9, 2018, 2:43 AM

#

Ok I'll help lol

eager burrow Oct 9, 2018, 2:43 AM

#

📎 unknown.png

fair wigeon Oct 9, 2018, 2:43 AM

#

What's the question?

eager burrow Oct 9, 2018, 2:43 AM

#

Im doing question 1

#

and i got to a point and i dont know what im doing anymore

fair wigeon Oct 9, 2018, 2:43 AM

#

Can you like crop the picture

#

I can't see shit

eager burrow Oct 9, 2018, 2:43 AM

#

open in orginal

#

in like a browser

#

and you should be able to zoom it

#

when you click it, in the bottom left corner

fair wigeon Oct 9, 2018, 2:45 AM

#

Ok

#

Yeah

#

So

#

Question #1

eager burrow Oct 9, 2018, 2:45 AM

#

c^2 -2c +1 +d^2= c^2 + 2ac + a^2 +d^2 -2db + b^2

#

i got up untill that

fair wigeon Oct 9, 2018, 2:45 AM

#

You use the distance formula to set both those distances equal to each other

eager burrow Oct 9, 2018, 2:45 AM

#

and im stuck

#

yea

#

i got theyre

fair wigeon Oct 9, 2018, 2:45 AM

#

That's all it wants I guess

eager burrow Oct 9, 2018, 2:46 AM

#

For (1) and (2) remember that if a point lies on the Unit Circle it must satisfy x
2 + y
2 = 1. Also, simplify the result as
much as possible.

#

thats in fine print

#

i think i have to solve the entire thing

#

but i dont understand how to do it

fair wigeon Oct 9, 2018, 2:48 AM

#

Huh

#

Ok so

#

Just that expression you got

#

Can be simplified further

#

Like, you can cross out the c^2

#

On both sides

#

Try and simplify it and see what happens

#

@eager burrow

eager burrow Oct 9, 2018, 2:49 AM

#

hmm

#

what is the x^2 + y^2 = 1

#

i have to satisfy that

fair wigeon Oct 9, 2018, 2:50 AM

#

That's the rule that radii are equal

#

That's more relevant for #2

eager burrow Oct 9, 2018, 2:53 AM

#

soo

#

a^2 + b^2 + 2ac -2db -2c +1 = 0

#

Now im here

fair wigeon Oct 9, 2018, 2:53 AM

#

Okay

#

So now

eager burrow Oct 9, 2018, 2:54 AM

#

but this has 4 different variables

fair wigeon Oct 9, 2018, 2:54 AM

#

Move the d and the C to other side

eager burrow Oct 9, 2018, 2:54 AM

#

i divided them out

#

ohh

#

wait

#

im confsued

#

which d and c

#

-2c

fair wigeon Oct 9, 2018, 2:54 AM

#

And then the left side becomes (a+b)^2+2ac

eager burrow Oct 9, 2018, 2:54 AM

#

and -2db

fair wigeon Oct 9, 2018, 2:55 AM

#

That's an annoying problem

#

Ok so

eager burrow Oct 9, 2018, 2:55 AM

#

im confused

#

lol

fair wigeon Oct 9, 2018, 2:55 AM

#

the last 2 terms of the left side

eager burrow Oct 9, 2018, 2:55 AM

#

-2db and -2c

fair wigeon Oct 9, 2018, 2:55 AM

#

-2db-2c

#

Yea

eager burrow Oct 9, 2018, 2:55 AM

#

yea

#

move those to other side

fair wigeon Oct 9, 2018, 2:56 AM

#

Move those over

eager burrow Oct 9, 2018, 2:56 AM

#

so the one side equals those

#

ok

#

leave the plus 1 on the side with the a and b

fair wigeon Oct 9, 2018, 2:56 AM

#

then you're left with (a+b)^2-2ac-1

#

On the left side

eager burrow Oct 9, 2018, 2:56 AM

#

yea

#

woops minus your right

fair wigeon Oct 9, 2018, 2:56 AM

#

Since radii are equal

#

(a+b)^2=1

eager burrow Oct 9, 2018, 2:57 AM

#

the a+b turns to 1

#

ok

#

i understand

#

soo much more now

fair wigeon Oct 9, 2018, 2:57 AM

#

-2ac-2=2db-2c+1

eager burrow Oct 9, 2018, 2:57 AM

#

so its 2ac = 2db +2c

#

how did you get -2ac

fair wigeon Oct 9, 2018, 2:58 AM

#

It stays

#

It was there before

#

I gtg lol sorry

eager burrow Oct 9, 2018, 2:59 AM

#

ohh nooo

#

<@&286206848099549185>

#

I still need help

#

anyonee out there

#

<@&286206848099549185>

#

i waited the 15 minutes

#

geez

#

anyone

steady sleet Oct 9, 2018, 3:22 AM

#

it's probably late for most people thonker

upper karma Oct 9, 2018, 4:12 AM

#

~~It's not late for me but I'm too lazy to help~~

elfin mica Oct 9, 2018, 4:21 AM

#

damn

twin prawn Oct 9, 2018, 11:40 AM

#

You're right about the last part, but that's not the same statement you proposed at the beginning

#

Of course linear pair implies supplementary angles, but NOT linear pair doesn't necessarily imply NOT supplementary

#

Think of two diagonally opposite angles in a square

#

They don't form a linear pair yet their angles add up to 180 degrees, making them supplementary

#

@upper karma

loud tiger Oct 9, 2018, 1:25 PM

#

Yo can i ask a simple geometry question

#

its really stupid but here idk

#

📎 USER_SCOPED_TEMP_DATA_orca-image--1153175274.jpeg_1539091217274.jpeg

#

i know how to answer it

#

but the illustration messed me up

#

So do i answer it like i would using hl congruence theorem

#

or answer it with "outside of the box" stuff

tiny grail Oct 9, 2018, 1:36 PM

#

@loud tiger realise that th common radii are equal length. They share a hypotenuse and a certain corresponding angle is a right angle

#

Then by RHS they are congruenr

#

This congruence means their corresponding angles are the same

loud tiger Oct 9, 2018, 1:51 PM

#

oh makes sense. Thanks

#

uh yo one last thing

#

📎 USER_SCOPED_TEMP_DATA_orca-image--945114133.jpeg_1539093055290.jpeg

#

uh

#

how do i solve this

opal blaze Oct 9, 2018, 2:02 PM

#

If a line is tangent to a circle you know that the angle between radius and line segment is always 90 degrees. Then you can use angle sum of triangle to find the last angle XYO @loud tiger

loud tiger Oct 9, 2018, 2:06 PM

#

uh. I still dont get it

opal blaze Oct 9, 2018, 2:06 PM

#

cathonk

#

What do you not understand?

loud tiger Oct 9, 2018, 2:10 PM

#

sorry but can you just tell me what i should do

#

And i'll try to understand what you said

opal blaze Oct 9, 2018, 2:15 PM

#

YXO is 90 degrees. Because the line segment is tangent to the circle. Therefore can we say that 58 + 90 + XYO = 180

#

Then you just solve for XYO

#

Lol

#

hype

loud tiger Oct 9, 2018, 2:19 PM

#

OHHHHHHHHHHHHH

#

OKAY DAMN

#

I can do the rest now thanks a lot ily

opal blaze Oct 9, 2018, 2:23 PM

#

Np Vsos

eager burrow Oct 10, 2018, 3:55 AM

#

hey

#

anyone can help with a graphing cotangent function

keen aspen Oct 10, 2018, 4:28 AM

#

Sure

#

If you work better with tangent, just flip the tangent function about the x acis and move it over pi/2

eager burrow Oct 10, 2018, 5:07 AM

#

hey

#

i got stuck on another problem while i was waiting lol

hard gale Oct 10, 2018, 5:10 AM

#

go for it

tiny grail Oct 10, 2018, 9:05 AM

#

=pup barycentric coordinates

charred spearBOT Oct 10, 2018, 9:05 AM

#

📎 result.png

#

Do more with Wolfram|Alpha pro

Query made by

@tiny grail

tiny grail Oct 10, 2018, 9:05 AM

#

=pup legendre’s symbol

charred spearBOT Oct 10, 2018, 9:05 AM

#

📎 result.png

#

Do more with Wolfram|Alpha pro

Query made by

@tiny grail

gritty flare Oct 10, 2018, 4:00 PM

#

If we have equlateral triangle with side k and then we draw circle around it, what is circles radius.

hard gale Oct 10, 2018, 4:30 PM

#

~~think before saying something that misses a step~~

#

By Pythagoras, heights (which happen to be the perpendicular bisectors also) in equilateral triangles are sqrt(3)*k/2

#

Then indeed those heights/perp bisectors intersect at their 2/3rds

#

So the center of the circumcircle is 2/3 * sqrt(3)*k/2 units away from each point

#

ie the radius of the circumcircle is k/sqrt(3)

tiny grail Oct 10, 2018, 5:19 PM

#

Just do sin rule lol

upper karma Oct 11, 2018, 1:36 AM

#

I got 0.097, is that right? @astral hornet

#

so if i round that, it's 0.10

astral hornet Oct 11, 2018, 1:38 AM

#

the question asks for the angle measure right?

upper karma Oct 11, 2018, 1:39 AM

#

yeah

astral hornet Oct 11, 2018, 1:40 AM

#

if sides are given: use inverse tangent to find angle. if angle is given, use tangent to find side ratios. .097 means you used just tangent

upper karma Oct 11, 2018, 1:41 AM

#

kk thanks, i might call you on help later tho xd

astral hornet Oct 11, 2018, 1:41 AM

#

ok

#

going from step 2 to 4, RS + ST was substituted into RT. since 2RS = RS + ST, and 2RS = RS + RS, ST must = RS in order to = RS + RS. since both RS and ST share S and are equal, S will be their midpoints, when R S T are collinear

upper karma Oct 11, 2018, 1:56 AM

#

@astral hornet I have an angle of elevation that the top is 53 degrees and it's 50 feet

#

How would I plug that in a calculator

#

I remember it that elevation is not inverse

#

but this sin cos and tan got me confused

astral hornet Oct 11, 2018, 2:14 AM

#

@upper karma draw the triangle first, and fill in what you know; this may help

upper karma Oct 11, 2018, 2:21 AM

#

So it's a

#

📎 Screenshot_20181010-222141.png

#

opp/adj

#

so it's tan

#

tan53 degrees

astral hornet Oct 11, 2018, 2:25 AM

#

@upper karma since tan(θ) = opp/adj, and you know adj = 50, let x = opp

#

then isolate x

upper karma Oct 11, 2018, 2:28 AM

#

adj is 50

#

i don't have a calculator to plug this into so this will be slightly difficult

#

I got 30

#

@astral hornet for opposite

astral hornet Oct 11, 2018, 2:29 AM

#

tan53 = x/50; x = 50tan53

#

solve for x and that's ur opp

upper karma Oct 11, 2018, 2:30 AM

#

the heck did you get 35

astral hornet Oct 11, 2018, 2:30 AM

#

53

upper karma Oct 11, 2018, 2:30 AM

#

imma need a bot for this

astral hornet Oct 11, 2018, 2:33 AM

#

@upper karma tan 53 = 1.3...

#

1.3*50=

upper karma Oct 11, 2018, 2:33 AM

#

65

astral hornet Oct 11, 2018, 2:33 AM

#

thats ur opp

upper karma Oct 11, 2018, 2:34 AM

#

yeah im having trouble without like

#

having one of those calculators

astral hornet Oct 11, 2018, 2:34 AM

#

what calc do you have?

#

in the meanwhile, you can just type ur sin cos tan stuff in search engine and a calc should show up

upper karma Oct 11, 2018, 2:35 AM

#

I don't know what they're called

#

but I don't have my own

#

TI-84?

astral hornet Oct 11, 2018, 2:36 AM

#

you can download wabbit as ti84 emu

covert idol Oct 11, 2018, 2:36 AM

#

== tan(53) * 50

charred spearBOT Oct 11, 2018, 2:36 AM

#

50×tan(53) = -21.5579098359782

upper karma Oct 11, 2018, 2:36 AM

#

oh my next question is writing tan60 in fraction

#

that's easy

covert idol Oct 11, 2018, 2:36 AM

#

Ah thats probably in radians

upper karma Oct 11, 2018, 2:36 AM

#

root 3 over 2

astral hornet Oct 11, 2018, 2:36 AM

#

30 60 90 sp tri

upper karma Oct 11, 2018, 2:37 AM

#

Why do simple radicals exist

#

smh, so complicated

#

📎 Screenshot_20181010-223728.png

astral hornet Oct 11, 2018, 2:37 AM

#

right isosceles

#

thus 45 45 90 sp rt

upper karma Oct 11, 2018, 2:38 AM

#

45 45 90 triangle

#

ok im actually stuck @astral hornet

#

i thought i knew the rule, but i don't

#

I know like the angles are 45 and 45

#

I remember you have to divide by 2

#

but im so lost

astral hornet Oct 11, 2018, 2:50 AM

#

given a triangle with legs x, x^2+x^2=sqrt(2x^2)=xsqrt2 via pythag. therefor the ratio is x : x : xsqrt2

#

substitute what you know into the ratio

upper karma Oct 11, 2018, 2:52 AM

#

x = 5 sqrt 2

astral hornet Oct 11, 2018, 2:53 AM

#

@upper karma x is legs

#

and you dont know the lengh yet

#

you do know the hyp is 5, 5 = xsqrt2

#

in 5 = xsqrt2, isolate x

upper karma Oct 11, 2018, 2:57 AM

#

oh i am so

#

so so so

#

lost.

astral hornet Oct 11, 2018, 2:59 AM

#

5 = xsqrt2, x = 5/sqrt2; rationalize it

upper karma Oct 11, 2018, 3:00 AM

#

ohhhhhhh

#

shit

#

this is making me look bad

#

i have like 20 more questions to go but these look relatively easy

#

I basically had 2/4.47

#

nevermind

#

Wait how do I write cos16 into terms of sine?

astral hornet Oct 11, 2018, 3:11 AM

#

cos(θ) = sin (90-θ)

upper karma Oct 11, 2018, 3:13 AM

#

how do you know this

astral hornet Oct 11, 2018, 3:14 AM

#

they're complementary functions

upper karma Oct 11, 2018, 3:17 AM

#

thanks for ya help bro @astral hornet

#

i needed help on this review

#

I missed 2 days of class, 👍

astral hornet Oct 11, 2018, 3:17 AM

#

cos(θ) = sin (90-θ) means cos of a number = sine of 90 minus that number btw

#

and np

late robin Oct 11, 2018, 6:19 AM

#

Hi

#

Can anyone help me with this question

#

📎 Screenshot_20181011-111011.png

#

Thank you @upper karma

#

At first I thought it 45 since ACB is 90

winged arch Oct 11, 2018, 7:44 AM

#

Hello guys can anyone help me with this question

#

in triangle ABC, B-M-C and BM = MC =6, if A-D-B and <BDM = < ACB AD=14 Find DB Edited :wrong problem I am stupid

#

This is how my prof drew it and how he solved it

#

I don't understand how he did this problem

winged arch Oct 11, 2018, 8:13 AM

#

<@&286206848099549185>

little osprey Oct 11, 2018, 8:16 AM

#

How would you draw it.

winged arch Oct 11, 2018, 8:19 AM

#

my prof drew it on the top left of this picture

#

wait

#

wrong picture

#

my bad

#

Yes this is his drawing

#

📎 20181009_172924.jpg

slim gorge Oct 11, 2018, 10:29 AM

#

anyone know spiral symmetry (complex numbers)?

#

wait nvm, i got it

tiny grail Oct 11, 2018, 10:35 AM

#

@slim gorge yes

#

Look at miquelbpoint and spiral centres

#

And complete quadrilaterals

slim gorge Oct 11, 2018, 12:42 PM

#

nah, i was just stupid :P

upper karma Oct 11, 2018, 5:42 PM

#

📎 unknown.png

heavy crag Oct 11, 2018, 6:58 PM

#

I need some vectors help if anyone is able to

#

It is fairly simple, but it's been a long while since I've done it

hard gale Oct 11, 2018, 7:01 PM

#

post your thing so that someone can help

heavy crag Oct 11, 2018, 7:01 PM

#

📎 unknown.png

#

I got part a) as: r = (3i + 5j +2k) + t (i + j + k)

#

But I can't recall how to do part b)

heavy crag Oct 11, 2018, 7:19 PM

#

nvm I got it

wild mirage Oct 11, 2018, 9:24 PM

#

Moved this question over to this channel, as it seem more suited for it, I'm just curious if I could use cosine law with this question, as it doesn't give enough information for the law for SSS and SAS

📎 2018-10-11_13-50-12.png

hard gale Oct 11, 2018, 9:27 PM

#

the two rafters have equal lengths, that's what you're forgetting I believe

wild mirage Oct 11, 2018, 9:27 PM

#

As you can get all the angles and just the one side

#

But what I find strange is the rafters are the unknowns

#

cutting out SAS and SSS

#

or am I just being blind

hard gale Oct 11, 2018, 9:29 PM

#

yeah, just solve for them

wild mirage Oct 11, 2018, 9:30 PM

#

How would I tho, as I don't have the information for the two requirements for the law

#

the main that the question is confusing me about

#

c^2 = 15.6^2 + b^2 - 2(15.6)(b)cos52

#

just can't wrap me around it

hard gale Oct 11, 2018, 9:32 PM

#

the fact that you know the rafters are equal shortcuts that SAS/SSS yup

#

the 2 rafters meet at an 52°

#

ie c is 15.6 here

#

and a=b

wild mirage Oct 11, 2018, 9:34 PM

#

So the question can't be solved with cosine but with sine law?

#

is that the point of the question lol

#

because the next one asks me to solve it using sine law

#

I'm sorry if I'm being really blunt about this

hard gale Oct 11, 2018, 9:36 PM

#

what you get from drawing the situation

📎 unknown.png

wild mirage Oct 11, 2018, 9:37 PM

#

wait

#

if a = b

#

that would shorten the equation

#

a^2 = 15.6^2 - 2(15.6)cos52

#

something like that right?

hard gale Oct 11, 2018, 9:38 PM

#

thonker

wild mirage Oct 11, 2018, 9:38 PM

#

man

#

this question is getting to me

hard gale Oct 11, 2018, 9:39 PM

#

c^2 = a^2 + b^2 - 2ab*cos(52)

#

(ie cosine rule)

#

now since a=b,

#

2a^2 - 2a^2*cos(52) = 15.6^2

dire lily Oct 11, 2018, 9:40 PM

#

AC:BC=4:3, hc=24, ACB=90° <- any idea how to solve this triangle?

wild mirage Oct 11, 2018, 9:41 PM

#

so I have to find the value of 2a^2

#

then / to get a/b

#

interesting

hard gale Oct 11, 2018, 9:41 PM

#

well a=b

#

why would you divide after?

wild mirage Oct 11, 2018, 9:42 PM

#

As I'm getting the value of both a + b together

hard gale Oct 11, 2018, 9:42 PM

#

ahhh lel yea

wild mirage Oct 11, 2018, 9:42 PM

#

would make sense to me to divide

hard gale Oct 11, 2018, 9:42 PM

#

i thought you said "i solve for a"

#

:/

wild mirage Oct 11, 2018, 9:43 PM

#

all good

#

thanks for pushing me on the right path goow

hard gale Oct 11, 2018, 9:43 PM

#

🍻

wild mirage Oct 11, 2018, 10:18 PM

#

So goow, i just wanna confirm I have it all good
15.6^2 = 2x^2 - 2x^2cos52
x^2 = 15.6^2 / (2- 2cos52)
x^2 = 15.6^2 / cos52 = 395.26
rad395.26
x = 19.88