#geometry-and-trigonometry

1 messages · Page 228 of 1

weary drift
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sure, ACD and ACE are a linear pair, so that's fine

surreal roost
grand shard
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hello i have question, how do i calculate the middle point of a circle?

the size of the circle is 35x35 (width: 35, height: 35)

worthy root
grand shard
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im kind of going coordinate-wise

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x, y

worthy root
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pi*35^2

dark sparrow
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@surreal roost 2.83 is not "rounded to the nearest tenth"

dreamy finch
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@surreal roost nearest tenth = nearest multiple of 1/10, ie, 0.1

upper karma
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What's your question

worthy root
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<@&286206848099549185> i reposted it it more than am hpur. Help me . 2*

mighty gull
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draw it out and do some principle of inclusion exclusion

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give me diagram first

upper karma
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Wtf is c

worthy root
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Wot ? @mighty gull

mighty gull
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draw it out

upper karma
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Yea

worthy root
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Wait

upper karma
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Literally

worthy root
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I got it

upper karma
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Drawl the angle

mighty gull
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lmfao

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"i got it"

worthy root
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Its 45-45-90 triangle

mighty gull
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you just pinged helper

worthy root
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I can do it i think

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I mean not the answer but a 45-45-90 triangle let me work over

mighty gull
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please draw out your things and actually try

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b4 pinging helpers

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ffs

worthy root
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I worked for an hour .

upper karma
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Bro draw the angle

worthy root
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Surfing on internet for answer

upper karma
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Draw another angle

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Draw more

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Until you have a polygon

worthy root
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Yes . Doing

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I am etting

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49(pi-\sqrt{2}/4

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Thats weong acc to my text

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Also people on internet say (49(pi-2)/4 is correct

south pebble
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can someone help me solve this?

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im getting an answer thats not making sense at all

worthy root
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isolate the sin(2x)

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,calc 150/2500

somber coyoteBOT
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Result:

0.06
worthy root
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,calc 0.06*9.81

somber coyoteBOT
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Result:

0.5886
south pebble
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arcsin right?

worthy root
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Yes

south pebble
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yes i did all that and im still not getting the right answer

worthy root
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You can use calc ?

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,w calc arcsin(0.5886)

somber coyoteBOT
south pebble
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then divide by 2?

worthy root
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Amd divide hy 2

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Yes

south pebble
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yup, still not getting the right answer for some reason..

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,calc 0.629326/2

somber coyoteBOT
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Result:

0.314663
worthy root
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Wdym by not getting right answer

south pebble
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im supposed to be getting a larger angle

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maybe because its in radians?

worthy root
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,w 150=(2500*sin(2x)/(9.81)

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Oh

somber coyoteBOT
worthy root
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Then use peridicty identities

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@south pebble

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Do you know the peridoicty identities?

south pebble
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err, not really no

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strange, i converted the answer to degrees using (180/pi)

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and its still not right..

worthy root
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sin(x+2pi)=sin(x)

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This type identity? @south pebble

south pebble
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are those also known as trig identities?

worthy root
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Yes? Maybe

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f(n+xp)=n is peridic function

south pebble
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i probably forgot

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i think im going to skip it for now

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thanks!

wind heart
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I kinda need help with this question

weary drift
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do you recall how to name a plane?

wind heart
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it needs three points that are not on the same line

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so wait would it be like

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Plane C D A

weary drift
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there you go

wind heart
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oh cool

worthy root
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Show that the minute hand of clock gains 5°30" on the hour hand in one minute .

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Is thera a mistake in the problem?

dark sparrow
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yeah should be 5°30'

worthy root
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Really man this textbook has hell.lot of mistakes

dark sparrow
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not 5°30"

worthy root
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Yes i know

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,w 1sec=xhr

somber coyoteBOT
worthy root
dark sparrow
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1/3600

worthy root
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Yes was just confirming

dark sparrow
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,w convert 1 second to hours

somber coyoteBOT
worthy root
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🤔

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1hr=60mins 1min=60sec

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1hr=3600secs

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I find the distance traveelid in 30sec

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That is

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36km/hr*30/3600hr

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3/10

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So i plugh this in arc lemght formula

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3/10=x

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The angle is just 18'

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But the textbook shows something else

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Woops

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I have to convert in degree

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Careless Krishna REEEE

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,calc 3/10*(180*7/22)

somber coyoteBOT
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Result:

17.181818181818
worthy root
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,calc 180*7

somber coyoteBOT
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Result:

1260
worthy root
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,calc 0.18*60

somber coyoteBOT
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Result:

10.8
worthy root
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Ann how i convert this recurring decimal radiam to degree

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I mean i have to do it till mimute and seconds

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,w convert 3/10radian into degress

somber coyoteBOT
worthy root
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,w convert (3/10)radian into degress

somber coyoteBOT
worthy root
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They roumd thay off

vagrant karma
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I need help

severe mortar
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I’m a little stuck

vagrant karma
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Same yo

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Mines harder

severe mortar
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yeah true

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would rlly appreciate it 🥺

vagrant karma
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Lemme see what I can do I’ll prob give you the wrong answer lmao

severe mortar
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delightful

vagrant karma
primal lynx
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y=x-3

severe mortar
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🥺

silent plank
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how big is the angle BAC?

severe mortar
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uhh I don’t know all I knwo is that

silent plank
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given the bearings to B and C from A, you have enough info to find angleBAC

severe mortar
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200-140

silent plank
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are you able to find BC now?

severe mortar
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Yes thanks

latent wave
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Hello, I'm new to Trigonometry, and I have a few simple questions: 1) How do I differentiate the graphs of Sine and Cosine visually? 2) When writing the equation of a Sine or Cosine function when only a graph is given, how do I know if it has been reflected?

vagrant karma
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I have more lol im dumb sorry

silent plank
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what have you tried?

vagrant karma
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I don’t where to start💀💀💀

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know^

silent plank
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distance formula?

stray spire
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could anyone help me with geometry ?

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this is the task -the lengths of the edges of the square are in the ratio 1: 2: 3. Prove that the surface of its slope is 9 times larger than the surface of its base

upper karma
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Not sure what to do

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the only way I can think of is using the law of sines to find the height! good luck : )

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SOHCAHTOA

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oh right there is that too haha. yeah pretty much similar

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Would it be sine=72/12

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Since Sine = opp/hyp

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sin(angle) = opp/hyp

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Wdym by Angel?

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oops

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My bad

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How do I use it to find length

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Do I need to use inverse of sin

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yep!

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wait

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And how do I do that?

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actually no haha

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Ah shit

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sin(72) = x/12

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Why?

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I am so confused rn

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so for the triangle you have. the hyp=12 and the angle is 72. we are trying to find the height (opp)

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Right

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just direct plugging in sin(angle) = opp/hyp

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sin(72) = opp/12

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Ihhh

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Makes sense

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: )

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So then I need to rearrange

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Or not?

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yes, what do you think the answer is?

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11.41

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I did 12sin(72)=x

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yep!

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Calculator says 11.41 (1.d.p)

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Yes!!

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Thank you so much

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you're very welcome

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Then

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I do height

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Times base

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So 11.41x16?

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correct

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Yes

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Thank you

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My retarded Spanish maths teacher can’t even tell me this

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Honestly, people like you are revolutionising the art of teaching mathematics

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haha thanks! I'd love to bring you to say that to the people I tutor xD

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Lmao lol

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May I ask for assistance for another question please?

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Or would that be too much?

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go for it, if it's under geo-trig post it here, if not just mention me in the appropriate channel

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I did some work on this one

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But I need help on figuring out perpendicular height

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you're almost done. you have a similar problem to the previous one: 7.2 is the adj, and you want the opposite. try drawing the triangle AVM in 2 dimensions, and you will definitely see it better. you have 2 known values and trying to find a third

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Not sure what the other value is

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so the angle is 58°, and the side length (adjacent) of the angle is 7.2cm, and we are trying to find VM (opposite), which trig uses that information?

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I can’t see 58

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I only see 68

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sorry 68. I'm blind

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Would we use Cos

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COH

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CAH*

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not quite, give me a moment

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SOG

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SOH*

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Sin

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Try now

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Further hint

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It’s not Sin?

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COS

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CAH

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Nope! You have Adj, and you are trying to find VM, Opp

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Adjacent/hyp

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Yes but, VM isn’t hyp

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AV is hyp

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Yes

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That’s what I thought

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Wait, how do you use SOHCAHTOA

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Is it by what values there are

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On specific positions

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On a triangle?

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Yes! So
Sin is Opp/Hyp
Cos is Adj/Hyp
Tan is Opp/Adj

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Which value do we have in our triangle? And which value do we want to find??

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Cos

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We only have hyp and adj

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So cos

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Which is adj/hyp

wet portal
#

V=1/3Ah

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h=?

upper karma
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So yes we are trying to find h

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Would it be tab

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Tan

wet portal
#

yes

upper karma
#

Wait why?

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I am so confused

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I was told

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Haha it’s ok. So h is VM

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Right

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And that’s the opposite

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Yes

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Yep, and you have an angle and the adjacent

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Yes

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Which one uses those 3

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Wdym?

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Which trig uses an angle, the adjacent, and the opposite?

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Tan?

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Yesh

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But tan

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Is opp/adj

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Yep

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How is angle involved

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It belongs to the triangle. If you look at the given information. It says VAM measures 68°

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And you already found that AC is 14.4, half of it is AM, which is 7.2

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Makes sense now? : )

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But I could use 7.2

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As adj

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Why is angle important to me?

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So you can find the height. Which you need to find the volume

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So what would tan equation look like

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Tan(angle) = opp/adj

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Assuming

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We needed to work out the angle

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And not height

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What would be equation

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Tan

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though we do have the angle, it's 68°, given from the question

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our goal is to find VM, the opposite

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What would be the general equation

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To find height

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Not angle

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I mean angle

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Not height

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there is nothing you need to do to find the angle, since it's already given as 68°

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Okay

wet portal
#

if assuming u needed to find it

upper karma
#

So I got 7.2/tan(68)

wet portal
#

it would depend on things that you knew about the triangle

upper karma
#

Is that correct

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To find opp

wet portal
#

if the equation is Tan(angle) = opp/adj

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you put in Tan(68) = x/7.2

upper karma
#

Yes

wet portal
#

how would you solve that

upper karma
#

You need to rearrange

wet portal
#

how

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you want to find x so what do you do next?

upper karma
#

7.2tan(68)=x

wet portal
#

yes

upper karma
#

My bad

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I mixed up opp and hyp

wet portal
#

yeah, it happens

upper karma
#

Thanks though

wet portal
#

i remember the time when i was studying sin,cos,tan and i was super tilted

upper karma
#

I got 17.82 (1.d.p)

wet portal
#

yep

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what next?

upper karma
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Put it in equarikj

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Equation

wet portal
#

yes

upper karma
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So 1/3x100

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X17.82

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100 being area of base

wet portal
#

yes

upper karma
#

👍

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Thank you guys

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For everything

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Damn

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anytime

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I still have a few questions to do

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Is that okay?

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Please tell me if it’s too much of your time

wet portal
#

yeah

upper karma
#

It is

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Okay

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My bad sorry I will leave then

wet portal
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nono, you can ask

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anytime

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😄

upper karma
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Oh sorry lol

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I made one annotation to this question

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I'm fine with as many questions as you want to ask, as long as you attempt them first

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I’ve tried to see if there are a few triangle theorems

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They didn’t work

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I just made one statement

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Saying it could be perpendicular

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But I am probably wrong

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Because I do know

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This one triangle theory

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Where one side doubles

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Like this

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So I did 45x2

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Yeah I am not so sure on the SAS, SSS, ASS system

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I know what they stand for

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But I don’t know how to implement them in the answers I make

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Basically, I don’t know how to use that system

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I just know they mean side,angle side etc

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that's fine. 2 triangles would be congruent under 3 conditions: SSS, SAS, ASA

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Only 3?

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yep

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No more no less?

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nope

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So how I do I know which one is which

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In other words, which one do I know is the correct one for this question?

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it depends really... I don't think there is a 100% way to tell, but most of the time if you are given an angle then you are using either SAS or ASA. Again, I never thought of which one to use, I just kept going until I satisfied one of them

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Hm okay

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for example, start by writing 10s all over the sides of the squares and you are basically almost done

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On the question?

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if you are allowed yes, or on a separate paper

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so now you have 2 identical pairs of sides of the triangles

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I am so confused

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Oh lord

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lol that's ok

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Why do I need to put 10s?

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because they are squares

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and squares have the same side lengths

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ABCD and AEFG

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so you have 8 side lengths of 10cm

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So where do I put 10s

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On sides of square?

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yeah, does that make sense though?

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Yes

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Because all sides are the same

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On a square

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yep haha, okay

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But I why you putting all over the squares?

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so that you can see now the triangles

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they both have 2 sides of 10s

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This okay?

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yep

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So now what do I do,

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okay let's think... we are at the point of S_S, where we just need to prove either the last side is identical, or the angle in between the sides is identical, does this make sense?

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Where did you get the 2 Ss?

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From*

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look are the triangles again, each has 2 sides with 10 cm

#

alright, so back to what I said, you either need SAS or SSS, but here, finding the last side to be the same can be quite challenging if at all possible. The question gives us an angle of 45°, and that's a good sign. Do you think you can finish it from here?

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Hmm

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Not sure

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Why is 45*a good sign?

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because it can be used to find the angles of the triangles that are in between the sides

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Okay

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And how would I do that?

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Would I use the triangle theorem

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Where the bottom part of triangle doubles

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nope... much easier than that

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try and see which angles you are trying to say are the same

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The 2 bottom ones

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not quite. you want the angle between the 10s of each triangle

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which ones are those? can you name them using letters?

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ABC and ACF,

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?*

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AGF*

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@upper karma

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those are the angles of the squares though... the angles we need to prove are the same are BAE and GAD

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those are the angles which are in between the 2 pairs of sides that are identical, can you see it?

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Yes I can

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What do we do with them

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find those angles! : )

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then tell me what you find out

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Red line represent 2 angles

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yep! those are 90°

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What is?

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EAG and DAB

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so draw a little square (90°) on each

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and now find BAE and GAD

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Why is it 90*

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Oh because they are on a square!!!

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😂 👍

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So wdym

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By find BAE and GAD

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the angle measures! what are they

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90*

harsh panther
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Hey,try highlighting the triangles you are looking to prove for themselves in some colour it may help with the imagination

upper karma
#

Would BAR

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BAE

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Be 90+45?

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@upper karma

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YES!! and GAD?

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should also be 90+45

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So 135

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yep... so now you can tell they are congruent using SAS

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can you see it? does it make sense

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Oh because the 2 angles in the 2 other angles I am trying to prove are equal angles?

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nooo you proved 2 sides are the same

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Right

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that's what the 10cm everywhere are for

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Right

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and then you are proving the angle between the 10cm pairs is the same as the other triangle

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which turned out to be 135°

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In the exams

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Can I just draw on diagram

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To get marks

harsh panther
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That would depend on your system

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School system*

upper karma
#

^

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Okay

vagrant karma
#

I have no idea what to do or where to start

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Please help

silent plank
#

how do you find the distance between two points?

vagrant karma
#

x1-x2/2

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NO PLUS

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and

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y1+y2/2

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NO WAIT THATS MIDPOINT

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LOL IM DUMB

weary drift
#

that'll get you the coords of the midpoint, plus you're missing parentheses

vagrant karma
#

but it’s the square root of (x2-x1)^2+(y2-y1)^2

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GIRL IDEK HOW I GOT INTO HONORS GEOMETRY LOLLL

weary drift
#

that looks better

somber coyoteBOT
vagrant karma
#

What

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That is not the answer to my question but ok lol

weary drift
#

you recalled the correct equation for the distance. i just typed it out in latex to confirm this is what you're talking about

vagrant karma
#

Ohhh

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Yes thank you

weary drift
#

isn't that hw site supposed to tell you if your answers are right?

vagrant karma
#

No

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I wish lol

weary drift
#

looks good

sly marlin
#

Isn't TRL an acute angle?

weary drift
#

@vagrant karma actually i don't know what "not an angle" means

sly marlin
#

I think maybe, syntax is wrong

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$\angle ABCD$ is totally not an angle

somber coyoteBOT
sly marlin
#

$\angle 45$ is totally not an angle too

somber coyoteBOT
sly marlin
#

And maybe involving nonexistent points, so for your diagram,
$\angle ABC$ is not an angle in the diagram

somber coyoteBOT
vagrant karma
#

@sly marlin trl is not an angle, bc it goes to the vertex then back.

dusty sleet
#

anyone here that could help me with differentials?

astral cedar
#

Hello

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m angle = 50 and m angle sgh = 120, prove angle fgh=170

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how to do

crude pelican
#

I checked the resources but i can't exactly find what i'm looking for in Geometry, Can anyone link me to a resource that may help me study? I'm doing Long-distance Formula with Shapes, finding Area & Perimeter and what not.

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Sorry if it's not clear enough, I'll add more context if required.

astral cedar
#

<@&286206848099549185> m angle = 50 and m angle sgh = 120, prove angle fgh=170
how to do

zenith ember
scarlet halo
spark stag
#

what are you asked to find

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where are you stuck

scarlet halo
#

find x

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but no idea where to start

spark stag
#

are you familiar with sine/cosine/tangent? maybe the acronym "SOH CAH TOA"?

scarlet halo
#

like legnth/since(angle)

spark stag
#

...what?

scarlet halo
#

i guess not then

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We did ratios today where y/x is the ratio and it should equal the side legnths ratio

spark stag
#

uhh

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do you have any more information?

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from the question, that is

scarlet halo
spark stag
#

yeah, you cant do these without trigonometric functions

scarlet halo
#

so u cant do it with the ratio based off an angle ?

silent plank
#

who wrote the approx 5/1?

scarlet halo
#

the book

silent plank
#

was the answer also from the book?

scarlet halo
#

yes

silent plank
#

nfi why they gave the approximation like that

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if they didn't plan on approximating the answer

scarlet halo
#

so u dont get it ?

silent plank
#

but yeh to get the answer you'd need the trig ratio for tan

scarlet halo
#

So u dont understand the way they got the answer

silent plank
#

i do.
tan(theta) = opp/adj

scarlet halo
#

can u explain how to do it ?

silent plank
#

have you leaned any trig at all?

scarlet halo
#

i dont belive so

silent plank
#

i'll provide enough to get you through the question

#

in a right triangle tan(angle) will give you the ratio of the opposite/adjacent sides

upper karma
#

anyone down to help me with reflections and translations

silent plank
#

to make calculations less tedious we are going to use theta which was calculated from 90-79 = 11 degrees

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what is the length of the side opposite theta?

scarlet halo
#

is it just tan( 11 ) ?

silent plank
#

tan(11) will be the ratio
but you need to know the sides involved

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so which side would be opposite theta (the side that theta isn't touching)

scarlet halo
#

x ?

silent plank
#

yeh

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and which side would be adjacent to theta?

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(the side that theta is touching that isn't the hypotenuse)

scarlet halo
#

O ok

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so the 95 length side

silent plank
#

yeh

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so what would the ratio be for tan(11 deg)

scarlet halo
#

x/95 ?

silent plank
#

yep

scarlet halo
#

so tan(11) = x/95 ?

silent plank
#

yeh

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and then solve for x and use a calculator

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hmm, it seems they rounded incorrectly

quiet mason
#

,w tan 11

somber coyoteBOT
quiet mason
#

,w cot 11

somber coyoteBOT
quiet mason
#

theyre right

scarlet halo
#

for some reason tan(11) *95 is -21465 on my calcuator

quiet mason
#

/95??

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uhm convert to degrees

silent plank
#

||18.466... rounds to 18.47 not 18.46||

quiet mason
#

tan 11 radians is -225

scarlet halo
#

um do u know how to change that is it in mode ?

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O nevermind i got it

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thanks

quiet mason
#

,w cot22*70

somber coyoteBOT
quiet mason
#

ye

#

youre correct

scarlet halo
#

thanks for all the help

upper karma
#

can anyone help me with translations and reflections

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Sure.

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Like the entire concept of it?

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like homework

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lol

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Oh.

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Send problem.

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Okay let's look at from A to B first.

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What x movements and what y movements does it take?

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im not sure

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what ya mean

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like a rgid motion?

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Yes.

#

It is a translation after all.

#

so i need

#

to find

#

bdc

#

?

#

You just need to find the horizontal movement and vertical movement from a to b...?

#

oo my b

#

i get it lol

#

👍

#

wait hold up

#

was i suppoed to do that

upper karma
#

@upper karma No.

#

From A to B.

#

It moves 2 horizontally and 3 vertically.

#

Wherever you got -5 and 1 there's no such thing.

#

So... if translations are marked by $T_{(x,y)}$

somber coyoteBOT
upper karma
#

Where x and y are the x and y movements.

#

What would the first translation be?

dusty sleet
#

use the graph below to find wich interval changes the smallest on avg

#

is this just y2-y1/x2-x1?

dark sparrow
dusty sleet
#

whats that

dark sparrow
#

you forgot parentheses

dusty sleet
#

oh sorry

dark sparrow
#

you didn't mean $y_2 - \frac{y_1}{x_2} - x_1$, did you?

somber coyoteBOT
dusty sleet
#

i ment this

dark sparrow
#

(y_B - y_A)/(x_B - x_A)

dusty sleet
#

allright, well is that all? all there is to differentials

#

how ever it is called in english

dark sparrow
#

difference quotient

#

yes

dusty sleet
#

okay thanks !

worthy root
#

Thats is called slope? @dark sparrow

dark sparrow
#

it's the slope of a line going through two points sure

worthy root
#

Yes.

rigid wharf
#

Which statement accurately describes how to perform a 180° rotation of point A (−2, 3) around the origin?

A- Create a circle with the origin as its center and a radius of the origin and point A, then locate a point on the circle that is 180° from point A.

B- Create a circle with point A as its center and a radius of the origin and point A, then locate a point on the circle that is 180° from point A.

C- Create a line parallel to the x‒axis from point A, and locate a point on the perpendicular line that is equidistant to the distance between the y-axis and A.

D- Create a line perpendicular to the y-axis from point A, and locate a point on the perpendicular line that is equidistant to the distance between the y-axis and A.

zenith ember
#

Which one do you think it is?

rigid wharf
#

A?

#

It is A

novel flax
#

A

silent plank
#

when is cosec positive?

#

which quadrants

#

does option A represent that?

rancid mantle
#

.

#
  1. A car whose speed is 20 m/s passes a stationary motorcycle which immediately gives chase with a
    constant acceleration of 2.4 m/s2
#

help plz

silent plank
#

this is neither geo nor trig nor a question

rancid mantle
#

a.How far will the motorcycle travel before catching the car?

#

oops LOL

sudden locust
jagged lantern
#

Can someone help me with something?
I have a question that asks "Prove the following trig identities: tanY cosY = sinY"

#

i don't know how to

#

if anyone can help please ping me 😄

harsh panther
#

Tell me what is sinY/cosY
For a right angled triangle where h represents the height of the side opposite to angle Y and b is the adjacent side while H is hypotenuse
Then tell me what tan Y is.

#

@jagged lantern

coarse bronze
#

stop advertising smh @sudden locust

upper karma
#

@sudden locust Imagine having anime music as your intro. Cool video ig.

novel flax
#

if you have a triangle with sides a b and c how do you find the area of the triangle

silent plank
#

have you ever heard of heron's?

median crown
#

@upper karma you can use heron's or law of cosines

#

you should probably use heron's

#

a, b, and c are the side lengths

silent plank
#

(s is called the semi-perimeter)

hard lotus
#

I have been stuck on this problem for a very long time. I have to prove they intersect and i just don't get what to do, I've asked friends who also try and fail and I even looked it up once after just having given up and I just don't get it.

Given a hexagon ABCDEF inscribed in a circle with AB = BC, CD = DE, EF = FA, show that AD, BE, and CF are concurrent.

#

gotta use i think inscribed angles and such to prove it but I'm just not getting it

#

can someone help please

#

i just feel stupid...

scarlet halo
upper karma
#

Yes.

#

But should be 69.22.

#

You end up with: 69.2204 which ~ 69.22.

upper karma
#

Hello there

#

Anyone here ?

#

;-;

dark sparrow
#

no obviously not

#

not until you post your question at least

#

@upper karma

tepid bone
dark sparrow
#

,rotate -90

somber coyoteBOT
jagged sandal
#

Being discussed in #help-2 for those that want to get updated on this.

dark sparrow
#

oh what the fuck

#

what part of "don't post the same problem across multiple channels" do people not understand

sly marlin
#

Update, finished being discussed in #help-2

sudden locust
#

@upper karma Haha thanks!

#

@coarse bronze Sorry if it came of as shameless

upper karma
#

Here is my question

#

Do ping me if anyone wants to discuss

dark sparrow
#

@upper karma what have you tried so far

upper karma
#

Yeah here is my approach

#

The thing is in the video using a different approach a solution has been shown with answer as around 32.6 (approx.) while by using my very simple reasoning i am getting 32.8 , is my approach to the problem correct ?

#

Here s the link to the video

dark sparrow
#

sqrt(3)?

upper karma
#

Yes , but is it not clear ?

dark sparrow
#

your three barely registers as such

#

anyway

#

this uh

#

this would make the vertical leg of that triangle sqrt(22)

upper karma
#

Ha ha i wonder you remember or not you helped in a permutation and combination a month ago and gave the same remarks about my handwriting

dark sparrow
#

and yet you've got it marked there as sqrt(3)

#

to the left

#

so what gives

upper karma
#

What ? Let me check

#

Thats just rough work not a marking

dark sparrow
#

your thing just falls apart

#

it all

#

falls apart

upper karma
#

Yes i recognised my mistake

#

I assumed the values , got lucky and therefore got a right answer

#

There are other combinations which would result into sqrt 17 but my foolish self failed to understand that

#

Thanks for help tho.

dark sparrow
#

and this all goes against your figure being a square

#

bc 4 + sqrt(3) is not 1 + sqrt(22)

upper karma
#

Yes , in excitement i kind of messed up the whole thing , but how did you do those marking so quick ? You have an apple pencil or stylus kind of thing ?

#

Oh wait those are typed

#

My bad

dark sparrow
#

yes those are typed

#

i did that in microsoft paint lol

hard lotus
#

i love how my question was just ignored

sly marlin
#

@hard lotus shall we go through it?

#

can't seem to find it, mind posting again?

#

okay this

hard lotus
#

yeah

sly marlin
#

Oh, the concurrency point is a centre of triangle ACE

#

Proof is literally about 5 lines at most

#

Focus on triangle ACE

#

What are lines AD, CF and BE?

hard lotus
#

they all converge at the same point

#

i mean intersect

sly marlin
#

no, what are they

hard lotus
#

and i think they are same length?

sly marlin
#

Not necessarily

hard lotus
#

they are angle bisectors?

sly marlin
#

How do you show that?

hard lotus
#

show they are angle bisectors?

sly marlin
#

yeah

#

of which angles?

hard lotus
#

they bisect angle B angle F and angle D

#

but how do i prove they are bisecting them

#

i mean i think they bisect those angles

sly marlin
#

focus on triangle ACE

#

well, you can find the angles based on the chord of the circle

#

@hard lotus

hard lotus
#

ok

sly marlin
#

try out

#

what angle relations do the equal chords give you?

night dew
#

Hello, I'm trying to understand what my notes are lul, i wrote that to check if something is linearly dependant, we can use this theorem:

somber coyoteBOT
night dew
#

however, I also noted that we can use his contraposed version:

#

but I can't understand what does the second one implies

somber coyoteBOT
spark stag
#

if vectors $\vec{a}_1, \vec{a}_2, \vec{a}_3$ are linearly independent, then $\lambda_1 \vec{a}_1 + \lambda_2 \vec{a}_2 + \lambda_3 \vec{a}_3 = 0$ if and only if all the scalars are 0 (i.e. $\lambda_1 = \lambda_2 = \lambda_3 = 0$)

somber coyoteBOT
night dew
#

omg yes, i'm dumb

spark stag
#

if they're linearly dependent, then there exist some scalars not all equal to 0 such that $\lambda_1 \vec{a}_1 + \lambda_2 \vec{a}_2 + \lambda_3 \vec{a}_3 = 0$

somber coyoteBOT
spark stag
#

so if you can show that those scalars exist and are not all zero

#

you've proven linear dependence

night dew
#

awesome ! thanks

spark stag
#

(this is usually done by just giving the scalars)

night dew
#

Problem: Be ABC a triangle, let I, J, K being defined as $\vec{AI} = {1\over 3}\vec{AB}, \vec{CJ} = {1\over 3}\vec{CA}, \vec{CK} = {1\over 3}\vec{BC}$. Show that I, J, K are aligned.

somber coyoteBOT
night dew
#

So I'd check if IJK are colinear by proving by example $\vec{IK} = \lambda\vec{IJ}$

somber coyoteBOT
night dew
#

but idk how I should actually prove that, how can I find lambda ? I'm not asking for a complete solution, just which way I should take, how should I approach this.

sly marlin
#

hmm

#

it looks like Menelaus

night dew
#

Haven't got that far in the theory, I'm at uni since 1 week only. Learned vector this week. LUL there must be an another way to prove it

#

but this indeed look like this case

sly marlin
#

Project onto an arbitrary vector

#

no, not that

#

Well you can check that two vectors are parallel

#

so you probably can use that to prove that the 3 points are collinear

night dew
#

which is $\vec{IK} = \lambda\vec{IJ}$

somber coyoteBOT
night dew
#

mhhh in the corrected exercices they compare IJ to JK and prove that it is equals

#

I mean yes but I would never know that without drawing the situation

sly marlin
#

yeah, this is probably the cleanest way to do it

#

without invoking menelaus

sudden locust
dark sparrow
#

familiar to the Pythagorean theorem

somber coyoteBOT
dark sparrow
#

yes, $(a \sin(C))^2 = a^2 \sin^2(C)$

somber coyoteBOT
dark sparrow
#

$(xy)^2 = x^2y^2$

somber coyoteBOT
dark sparrow
#

I just know there are some rules about inverse trig functions and so on
:?

somber coyoteBOT
dark sparrow
#

cos^-1 is an awful notation that should never be used because cos doesn't have a true inverse

upper karma
#

<@&286206848099549185> what is section formulae?

upper karma
#

@dark sparrow what should be used? arccos?

dark sparrow
#

yes

upper karma
#

Why so? I think its common knowledge on the restriction of the domain

dark sparrow
#

i've seen it misused one too many times

quiet mason
#

@upper karma a+b=b+a

#

and please read rules

upper karma
#

i said the section formula in coordinate geometry?

#

how do you prove it?

dark sparrow
#

what is the "section formula"

dark sparrow
#

extended law of sines?

#

what... is that meant to be

#

oh the circumcircle radius thing

#

...honestly there's no good answer whether that's "3rd grade" or not

#

why does it matter

#

like... idk, i wouldn't say trig itself is a thing that could be meaningfully taught as early as 3rd grade

#

you're not seriously suggesting giving a problem like that to 9 y/os are you

#

i mean

#

i guess a smart 9 y/o could have the necessary algebra background i guess

#

but this all sounds a bit... out there to me

flint pelican
#

Dude that problem is insane I can’t even do that and you want to give that to a 3rd grader

#

Kids these days are so smart

#

Guys for this I can see now that 12^2 144 so if we double the force since they are inversely related that means that we need to divide 144 by 2 I think so 72

#

But the problem factors 72 into 6 square root of 2 and I’m not sure why

flint pelican
#

<@&286206848099549185>

lunar crow
#

is that

#

the ACT

flint pelican
#

Yes this is a question from an act practice test

upper karma
#

how do i find ps? im retarded

mighty gull
#

so the just want the radial angle right

#

have you heard of inscribed angle theorem

#

@upper karma

upper karma
#

yes it htought that the angle was 95 or 85 but im not sure

#

the arc*

mighty gull
#

can you apply inscribed angle theorem here

upper karma
#

i only had 2 opportunity to check if the answer was correct so idk if my answer was correct

#

and i wanted to know

mighty gull
#

95 and 85 arent answers

upper karma
#

ok

#

oh

#

its fucking 80

#

lol

#

im retarded

#

wtf

#

i didn't even see it

mighty gull
#

yeah. dw its fine, we all miss things like this all the time

upper karma
#

haha

#

i was trying to figure out the left and right angles from the center of the circle

#

and i didn't even see that the 40

mighty gull
#

its fine

flint pelican
primal lynx
#

well if ur asking about the first one

#

choice k is the choice that makes the least sense

#

bc it says varies inversely with the square of the distance

#

so farther away less powerful

#

k is the only choice thats further

#

but if you were to write an expression with proportionality constant say k

#

you can write the inverse square as like 1/d^2 is equal to k 1/r^2

#

but k is 2 right

#

bc twice as strong

#

and d is already 12

#

then you get j

flint pelican
#

Yeah the answer is j but like

#

This is what I said earlier

#

Guys for this I can see now that 12^2 144 so if we double the force since they are inversely related that means that we need to divide 144 by 2 I think so 72

#

But the problem factors 72 into 6 square root of 2 and I’m not sure why

spark stag
#

they're not inversely related

#

there's an inverse relation with the square of the distance

#

so suppose the distance is 2, then $F \propto \frac{1}{d^2} = \frac{1}{2^2}$

somber coyoteBOT
spark stag
#

in this case, we have $F$ and we want $2F$

somber coyoteBOT
spark stag
#

we know $F \propto \frac{1}{d^2}$, so how do we double F?

somber coyoteBOT
flint pelican
#

By dividing 144 by 2

#

Right?

spark stag
#

so you're saying that it needs to get farther away for the magnet to get stronger?

#

what we're trying to do is change the distance

#

144 represents the distance squared

#

not the distance

#

you're right that we want the distance squared to be 72

flint pelican
#

Ooooooooooooooooooooooooooooo

spark stag
#

so what does the distance have to be?

flint pelican
#

The square root of 72

spark stag
#

right

#

now make that a mixed radical

flint pelican
#

Because 72 would be the distance squared

#

Yeah then I see that factors to 6 square root of 2

#

Thank you

spark stag
#

sounds good.

#

and we can test this

#

,calc 1/(12^2)

somber coyoteBOT
#

Result:

0.0069444444444444
spark stag
#

,calc 1/((6sqrt(2))^2)

somber coyoteBOT
#

Result:

0.013888888888889
spark stag
#

,calc 0.13888888 / 2

somber coyoteBOT
#

Result:

0.06944444
spark stag
#

er

#

missed a 0

#

,calc 0.01388888 / 2

somber coyoteBOT
#

Result:

0.00694444
spark stag
#

there we go

#

yep, thats correct.

primal lynx
#

lol

median crown
#

Flip everything upside down

#

nice dude

#

spilled your gfuel

#

ye u did it right

#

except

#

your scale labels are wrong

#

you put pi/2<pi/4

#

yeah

#

yeah

#

you have pi/3 on the left side of the y axis too

#

wtf

#

why

#

you should fix your handwriting

#

the handwriting litearlly makes it look like a 3

#

sure

solid nexus
#

hi can someone help me?

sly marlin
#

JustAsk @solid nexus

delicate lake
wise pawn
#

do you know SOH CAH TOA?

silent plank
#

which one do you think it is and why?

delicate lake
#

This trade school is giving me trig questions and I've never even took the class.

#

Trying to teach myself through online videos

#

Trying to find hypotenuse.. so i use Tan? @silent plank

silent plank
#

no

#

what is the ratio of tan(x)?

#

do a quick search and/or use the mnemonic shown above

delicate lake
#

This is above my pay grade. I have TI-84 Plus calculator but not every experienced with it

silent plank
#

what i'm asking has nothing to do with a calculator

delicate lake
#

I'm literally trying to teach myself

silent plank
#

and what does it say on your notes?

#

tan(\theta) = ?

delicate lake
#

Opposite/Adjacent

silent plank
#

would that be appropriate here?

delicate lake
#

Oh no.. lol but there is no 2 sides given.

silent plank
#

which side is given relative to the angle?

umbral snow
#

c isn't given, but pretend it is for now

delicate lake
#

Adjacent and Hypotenuse so i use COS

silent plank
#

yes

delicate lake
#

?

#

Oh snap

silent plank
#

well to be more specific, adj is given, hyp is unknown so you use cos

delicate lake
#

.883 is the answer

silent plank
#

no

delicate lake
#

Rip

silent plank
#

can the hypotenuse be shorter than the other sides?

#

you must've done something wrong in your calculattions

#

what equation did you start with?

delicate lake
umbral snow
#

You're getting ahead of yourself. What's your cos equation?

delicate lake
#

Adjacent divided by hypotenuse but hypotenuse isn't given

graceful hemlock
#

Is it in radians or degree mode LOL

silent plank
#

cos(28 deg) = adj/hyp = ?

umbral snow
#

That's okay! Write it out anyway

silent plank
#

what is the adjacent side?

delicate lake
#

1.5

silent plank
#

what is the hypotenuse represented by?

delicate lake
#

C

silent plank
#

what is adj/hyp

delicate lake
#

1.5/C

silent plank
#

and what will cos(28 deg) be?

delicate lake
#

Thank you.

#

1.5/.8829

#

=1.69

silent plank
#

that wasn't what i asked for but you found the expression for C
be careful with rounding

#

technically the value they provided is wrong. but i think that's what they want you to choose.

delicate lake
#

I will re-read this convo for future simliar problems.

"which side is given relative to the angle?" Helps me decide which function to use.

But i do see where I was confused.

silent plank
#

,w 1.5/cos(28 deg) 4 decimal places

somber coyoteBOT
delicate lake
#

Ok

#

Much appreciated.

silent plank
#

based on the options it seems that they rounded before dividing

#

which you shouldn't do

#

,w 1.5/0.883 4 decimal places

somber coyoteBOT
silent plank
#

as mentioned above, it seems they want you to pick 1.6988, but the "correct" value rounded to 4dp would be 1.6989

delicate lake
quiet mason
#

👌

delicate lake
#

Sweet thanks. Appreciate the patience

novel flax
#

sin x = opp/hyp
sin 39 deg = 1.375 / c
c * sin 39 deg = 1.375
c = 1.375 / (sin 39 deg)
c = 2.1849

#

you are correct @delicate lake

flint pelican
#

Lost in 55 and 56

#

For 56 isn’t the 5 the radius so 5 squared is 25 and then the height is 12 since this is a 51213 triangle so that’s 25pi*12=942.478 and divided by 3=314

#

So that’s 100pi but that isn’t the answer the answer is j

#

And for 55 what I guessed was that since 2 angles are 60 that must mean the other 2 are 120

#

So I multiplied 4 by 2 to get 8 since 60*2=120