#geometry-and-trigonometry
1 messages · Page 294 of 1
sigh
Here, %300 increases to %500. If you go outside protests, you get arrrested
Money is everything. Dollar is important.
If you go outside to protest, loot buildings, and burn buildings down, no one cares.
Since it's in the name of justice.
I gtg lol.
cya
Gl on your endeavors :3
Np lol.
@ripe osprey
@upper karma Lol it's right in everyone's face.
Everyone knows America gonna be fucking wack in a few years, they just think it's either these shit political correctness police that'll cause it.
Or white privilege.
That'll ruin America.

@ripe osprey Nerd.
ah good race and politics in the #geometry-and-trigonometry channel
Race and politics is the fundamentals of geometry.
Or it's the other way around.
fuck off yall this shit in particular does NOT belong in the channel yall chose to post it in

staph pls
Hey all, hopefully this is the appropriate channel, but I'm wondering if someone could explain this in a bit more of a simplistic manner
I'm not quite understanding the point
This follows the irrationality of root 2 proof
so the way i'm interpretting it is that the greeks were saying, give me two vectors, and the resultant vectors magnitude can be divided into 2 pieces, and both would represent the magnitude of the original vectors
Which i'm kinda confused about
or is it saying give me two line segments and i can a line that isn't the resultant
hm
idk
Yeah but if someone could please dumb this down it would be appreciated 😄
It is saying that Greeks thought lengths were “constructible” only if the length was rational
But this is not the case. Make a right triangle with leg lengths of 1, then the hypotenuse construction has length sqrt(2)
“Divides evenly” means hypotenuse construction I suppose (when interpreted geometrically)
The rational multiple part is another way of saying the same thing, but with multiplication instead of division
I don't get whats even about the hypotenuse construction though
I think it means “connected”
wdym by connected? sorry for my unfamiliarity of the terminology and stuff
Suppose I put two lines of length 1 perpendicular to each other and touching at only their end points
The Greeks would say
There is a line of rational length which connects the other end points on the lines together
but the straight line from the tip of one line to the tail of the other would be root 2
since it's the shortest path
Yes, so the Greeks were wrong
If you view multiplication of 2 lines as a rectangle
Then that’s how hypotenuse being related to “divides evenly” might make sense
I don’t exactly know how the book is using that term but that’s my guess
is this channel free?
i guess it is
can you give me a hint to prove this proposition:
Let A be a point, (D) a line, H a point such that (AH) is perpendicular to (D). The distance AH is equal to the distance from A to (D).
what i think we are going to use is the following property:
The distance between a point A and a line (D) is the smallest distance between point A and a point H of line (D).
and i think i need to prove that the smallest distance "happens" when (AH) is perpendicular to (D) but i dont know how
are we going to use angles
or maybe pythagoras
nevermind i got it
When dealing with trig values of special angles and forming a right triangle in a unit circle, how would you figure out the lengths of the adjacent and opposite side if the triangle isn't isosceles?
I don’t understand the problem. Teacher assigned some optional work
If you know the height and hypotenuse of a right triangle, then you know the base.
@royal edge
I still don’t get it
Let's say I attached 5 wires all of known length to the same height on a post
Then all of the wires will attach to the ground at the same distance away from the sign
Ah I see! Thanks
h
hi can someone give me a hint idk what to start with with this:
Let (C1) and (C2) be two circles which intersect in points A and B.
(L) is a line which goes through A.
(L') is a line which goes through B.
C and E are respectively the intersections of (L) with (C1) and (C2).
D and F are respectively the intersections of (L') with (C1) and (C2).
Show that (CD) and (EF) are parallel lines.
diagram i made on geogebra
i first though about using thales proportionality theorem but it seems like it doesnt work but idk
apart from that i am stuck
maybe similar triangles
with AA
FGE = CGD is clear i may need to prove CDG = GFE or GCD =GEF
consider stuff like inscribed angle theorem, cyclic quadrilaterals
the inscribed angle theorem is the one about the center, double half etc?
like AMB = 1/2 AOB
Got it
Consider cyclic quadrilater CABD
<CAB+<BDC=180, <CAB+<BAG=180
You continue...
@charred zephyr
Okay so what? @arctic vortex
So first idk why the guy decided to put b instead of putting literally 20 but ok
lol
And do you know the general approach to these type of problems or you are new to them?
new to them
i have a lot of homework to do which is why im asking for help here, and studying really hard to understand them once im done with everything
Okay so
How to Calculate the Scale Factor of Two Shapes. Part of the series: Geometry Tips. You can calculate the scale factor of two shapes using a very specific method. Calculate the scale factor of two shapes with help from a longtime high school math tutor in this free video clip....
For the basic understanding
oh ok
wait but i only have 30 mins to finish these questions lol
i already did 2
i have 2 left
both like this
k
We'll work it out after together
20/7 is not equal to 29/10.
Oh ok nvm
its 2.85
no
20 / 7
20/7 is not 285/100 either
oh
do not round intermediate calculations at all
oh
only round the final answer and ONLY if you're asked to do so.
do not use a calculator
ok
are you allergic to fractions or something?
And you aren't appropiately applying it
yeah lol
aledium what contrals is doing is fine in principle
it's the inappropriate rounding that i am pointing out

20 / 7 ?
ohh
so the answer is like 34
if u multiply 12 * 20/7
wait
1 second
i undestand it
bc its scale factor
ok im stupid
oh wow haha i wouldve done that
Welp
,calc 12*20/7
Result:
34.285714285714
thats a nice bot
Latex died again
34.3 is the answer you will get after rounding to one decimal place.
oh ok thanks !
note that rounding prior to multiplication by 12 would have resulted in an incorrect answer.
aledium what contrals is doing is fine in principle
Yeah i confused the y with the b
Al𝟛dium:
Now @arctic vortex
if two triangles are similar can we directly apply thales theorem to prove parallelism
ok
Al𝟛dium:
Okay not theta but its to name it
k
Can you post the original question
Okay better
Again lol
@upper karma what?
if two triangles are similar can we directly apply thales theorem to prove parallelism
@charred zephyr can someone answer me
if two triangles have same angles does it mean their bases are parallel when they're put in the same summit form or butterfly configuration
hey
hello
@upper karma im not sure how id draw it
So
Think of unit circle
23π/6 seems VERY big, compared to what we will use to graph it
Bc remember its 0, 2π
And 23π/6 is WAY bigger than 2π, do you agree? @gloomy slate
i'll just wait
Al𝟛dium:
What do you mean by its on our 0?
Our 0, 2π region
4th
Now draw it, it'll help you visualise it
We are almost done
Just wanna build the base strongly
Al𝟛dium:
Howd you get that equation
Trigonometry
sqrt(3)/2?
Yep
That is for cosine
BUT
$\cos(\theta)=\cos(2π-\theta)$ IS TRUE BUT NOT $\sin(\theta)=\sin(2π-\theta)$
Al𝟛dium:
Ok?
i see that chart has 11π/6 as well
@gloomy slate yeah for the sine you have to check on 11π/6
But for cosine check for π/6 which is more comfortable bc of the identity we said above
🙋♀️
but when they ask something -3pi/4
Yes?
I can refer to the chart and see 3pi/4 is this
but when they ask for the negative version
sin turns into -sqrt(2)/2 as well
but how would I know that based off that circle chart or whatever
Al𝟛dium:
And THIS is what you should use
it's like functions parity
$\sin(-\frac{3π}{4})=-\sin(\frac{3π}{4})$ which of you can check on the unit circle
Yes
Al𝟛dium:
@gloomy slate
hmm okay thanks
Np!
if ABC and ADE are similar we do agree that angle a should be equal to the red angle and angle b should be equal to the blue one isnt it
Uh
ok
but thanks anyways
but just if you know would angle a be equal to purple or green angle? same question for angle b?
forgot to say the little triangle is similar to the bigger
it could be either
it depends on some specific thing?
depends if the top and bottom lines are parallel
so similar triangles dont necessarily have parallel bases?
on what?
Their Relative position
If you can gave an example, it'd made it easier for us to explain
Like not an invented one
Lmao
ok wait
ABCD is a square of lenght 4
Diagnols AC and BD intersect in point G
The cocyclic points A;E;B;F form quadrilateral AEBF
Angle BOD is equal to 170° with O center of the circle
Show that AD and BC are same line or parallel
corrected something...
as always, draw a diagram
uh you know what just cancel my question im too tired to follow the lines
F
We can even cancel you if we want...
can we cancel their name
What's some tips to find the family of lines tangent to a circle, if we know its radius and origin?
can anyone help me with like 15 geometry questions about triangle congruency?
oh boy
Post them
Aight
Take as much as you need
ok tysm
actually you can send the questions now so i have time to look at them
What's the difference between a and c
is there gonna be fourteen more of these?
@upper karma the difference is in which vertices are paired
no there are like 15 questions on my homework packet but i dont undestand like 5
and the rest i just ask u to check them
so can u help me with question 1 pls ??
@dark sparrow srry for ping
ok so what's troubling you here
i dont understand q#1
at all
i see the triangles
so i find which of them are similar/
the lines
you are given four similarity statements
you are asked to choose which one of them is actually true for the diagram
i thought that was what we were gonna do anyway
oh yeah
and wait what is the "B"
in the question
does it belong to the big small or both
it's (2,2) as far as i can tell
anyway, you solve your 15 questions, give me the questions and your answers, and i check them and tell you which ones you got wrong
ok
wait whats the answer to #1
or what does b mean
what triangle does b belong to
ohh
it's the intersection of AC and DE
the legs of ABD are in a ratio of 3:2, as opposed to those of EBA which are in 2:1
EB/BA = 2 = DB/BC
first one only
^
just because it looks like a parallelogram doesn't mean it is one
Sad truth
Yes
pinging HoboSas pings me for some reason
i clicked hobo and i thought it would direct to hobosas
why did u select C
did u just guess
look at the coordinates of points K, L and M
its clearly d
k is located at (1,1)
for L y = 4 and x = 5
for M y = 1 and x = 5
no i went to desmos.com and i put all the points in
why are the minus signs weirdly offset
^
oh
while KLM here is one
Try drawing every triangle
yeah thats what i did
and c looked like the best option
wait
is it d then
@dark sparrow
yes
really?
no joke like really
how is it d that was my last option
@dark sparrow whats the second one ??
you should stop guessing "Oh ummmm is it C?"
you should actually know why your choosing an option
it's one of the angle congruences
multichoice homework sucks
honestly
this is a poorly worded question since there are multiple correct answers
or wait hold on
?
no wait there actually is only one my bad
?
yeah
i am not spoiling the answer.
oh
now if there arent more than 1 correct answers, i would be pissed.
and nah dont spoil it
because it makes sense unlike a where bc =/ qr
okay so let's just establish this: it's gotta be one of the ratios and one of the angle congruencies
yeah
$\Delta ABC \sim \Delta QRS$
trece:
triangle abc is similar to triangle qrs ?
ok
of course
ann gave u a hint already
okay so let's just establish this: it's gotta be one of the ratios and one of the angle congruencies
option a would require angle C = angle Q to work
but we don't have that in the options
wait
uh
no, option a doesn't work at all
BC would correspond to RS, not QR, under the similarity statement they give you
option a is out entirely
what do u think about f
its like the same
so were between b),c) and e),f)
do u know trigonometry
no
im in geometry
not trigonometry
im taking that next year i think
here is the question again by the way
so u dont have to scroll up
highlight the sides and angles of your choice on the diagram
and see if it satisfies SAS
So what are the answers?
SAS stands for Side angle side
its either f and e or c and b
specifically the congruent angle needs to be between the 2 corresponding sides
That's the key
yeah i know sss and sas and asa and stuff
the ratio between two sides is the same as the ratio between another two sides
also the included angles are equal
thats how u know
oh
yay only 4 more
and then i am done with homew ork for the week
and i can do anything iwant
yay
you should check again whether e,f is actually valid
how do i check that
You think
oh
yeah i think that e and f are correct
or is it b and e
@silent plank i think its b and e
Are you sure <C is between AB and BC
actually
highlight the sides and angles of your choice on the diagram
and see if it satisfies SAS
angle C is not between AB and BC
no
therefore its not that
oh so its not b and e
So it's?
e and f
angle C is not between AB and BC
^
Stop guessing
ok
Sit down and think about it
highlight the sides and angles of your choice on the diagram
and see if it satisfies SAS
ok
like use paint or highlight it on paper or something
which options are you using to get those?
where are you getting <B = <R though?
im not getting that
then why is it indicated on the diagram
bc its the angle
that's not what i'm telling you to do
oh
b c
wait its b c
look contrals, the option c is basically saying that the ratio between AB and QR is the same as ratio between AC and QS
the angle between AB and AC is A right?
and the angle between QR and QS is Q
makes sense now?
oh
we can move on to the next question now, i dont wanna leave u all day long on the same one xD
so a is the center of ab ac
and q is the center of qr q
qs
so the answer is b c
i wouldnt say center
A is the angle between AB and AC
ok now i finished everything else
can u just check
@warm basin can u check these
@dark sparrow
first one is correct, second one isn't
you posted two problems
on the second one i want u to look on option c and d
do they?
okay good
so d it is
just remember, a correct answer is a answer that makes sense
AND I ONLY ASKED HELP FOR LIKE 5
IM SO HAPPYT
DAD MOM
GDT HTE CMAREA
looks like
i dont need to do
the problem sets
because i am just too smart
yesssss
i am just too smart
im sorry son but u shouldve gotten 95% or better
oh
how many problems were there in total
24
ok ok
i actually got 1 half wrong
because i misread it
wait a minute
i shouldve gotten a 100
wtf i misread #24 and #5
but i make 1 mistake on hte half wrong question
Good job
thanks
21,6 questions right
21.6 are right out of 24
so 2.5
24 times 0.9
2 wrong
xD
lol
,calc 34.04/38
Result:
0.89578947368421
who the fk gives 0.04 points
^
probably non engineers
and srry if i was annoying
this is my first time doing something like geometry
im more of an algebra person
Someone please send a hard geometry problem
🤔
Someone please send a hard geometry problem
I agree
Using a ruler, what's the circumference of this circle?
7
umm is it c)?
Measure the diameter then multiply by pi
Also depends on the browser zoom and whether you clicked on the image or not.
can anyone help me with this test correction
CBE + ABE = CBA
x=139
wait how
What
I have no idea how to say that in english
oh
Alternates angles?
ok thats fine
Something like that
Yes
here
yeah
I called BCF x
What don't you understand
the question
Given that <BCF = 139, find <CBA
No, it's a
how do i do that
By noticing that x + CBE =180, CBE + ABE = CBA, with ABE=90
Why is a line's gradient defined as rise/run and not run/rise?
Given point $A = (0, -3)$ and Point $B = (5,7)$, and Point P such that $AP:PB = 2:3$, why does P not lie on the coordinates $P = (\frac{2(5+0)}{5}), (\frac{2(7-3)}{5})$?
dlp ω:
And lies on $P = (\frac{2(5-0)}{5}, \frac{2(7--3)}{5}-3)$ instead?
dlp ω:
I understand the -3 in the y point comes from $\bar{AB} \equiv y = 2x-3$, but my question is why is subtraction performed on the 2 x, y coordinates as opposed to addition?
dlp ω:
Why is addition performed when finding the midpoint of a segment, but not in this case?
In fact, upon trying a variety of divisors, I have found 2 is the only non-1 divisor which allows a point to lie on the original line.
Actually, why is the y-intercept factored into the former equation, but not the latter? It seems like something intuitive but the inconsistencies may be putting me off.
damnit where is @earnest pagoda when you need him
How do I prove that a curve with the equation $x^2 + y^2 = n, {x, y>0}$ does not pass through the origin of the plane?
plugging in (x,y) = (0,0) results in n = 0, which obviously goes against your assumption that n > 0.
@steep temple
look for section formula for what you asked previously
corrected to what I meant
dlp ω:
the origin is not even in the region {x,y > 0}
i'm just pointing out the obvious
(that was not sarcasm)
look for section formula for what you asked previously
@earnest pagoda my question was more like why does the section formula differ from the midpoint formula?
midpoint formula is section formula with ratio 1:1
got it.
well given that they basically tell you $m \angle CBE = 41\dg$, and that $ABDE$ is a rectangle, it shouldn't be too hard to calculate
Ann:
unless you're allergic to addition or the number ninety
what are lowercase a and lowercase b?
neither option a nor option b lists 90 as its value
the angle a
and the angle b
because there is a right angle and same side interior angles are a thing so does that mean e is 90
and since its a rectangle everything has to equal 90
so A=90 and B=90?
wait no that doesnt make sense
@dark sparrow im confused
don't refer to angles by single letters unless it is unambiguous which angle is referred to
which in the case of angle B it is not
here's the diagram stripped of everything except the four relevant points
131
ok im stupid
i didnt see that
i know the answer to this but idk how to prove the answer
is correct
@dark sparrow
what?
i know the answer to this but idk how to prove the answer but idk how to prove this is correct
is it A?
i think its A
because it is supplementary
w and 118
and 118 + w must equal 180
you answered your own question
can someone help me with this question
my bad I went to a channel to find the answer but realised there is a speific one for geometry
use trigonometry
the question is supposed to be geometry based
no sucette
@tidal river thank you for completely ignoring my actual question.
let me repeat myself.
what is giving you trouble for this problem?
you know people dont pay attention to thing sometimes and its better to react in a nice way if its the first time
i don't know how you make a list for descending or ascending order
do you know what it means for a collection of things to be listed in descending order?
do you know what "descending order" means?
from greatest to least
ok great
so the problem asks you
"if the angles are ordered from greatest to least by measure, then will the result be A, C, B?"
can you give me the answer and explain how you got to it
"is it true that A is the largest angle, C is the second-largest, and B is the smallest"?
i need to learn
here
i dumbed it down for you as far as i possibly could
i'm not giving you the answer to a true/false question
Christ man, getting an answer handed over to you is not a good way to learn, you gotta struggle.
@tidal river if you want to give up then please let me know so that i know not to expect a response from you
I trying to learn this out of my own interest. Not to just get an answer handed over to me. If tell me the answer and explain how you got there then maybe I'll understand
the question asks you
"is it true that A is the largest angle, C is the second-largest, and B is the smallest"?
but theyre trying to lead you to the answer step by step
there arent even that many steps
im just trying my best to reword the question in a way that is more understandable to you
@tidal river take a break for a couple of mins and then reread a "triangles" section of your favorite basic geometry book. This is actually a VERY simple question once you remember the basics, I'm sure it will click for you when you refresh that part.
I have an algebra book lol, called algebra demystified
And plus, isn’t Sine law or cosine law acceptable to find the angles of A, B and C
@earnest pagoda i have read the brilliant article on the section formula and i still do not see where subtraction comes into play
this is the closest thing that comes to subtraction and even then i think it is irrelevant to my case
going by their logic, https://cdn.discordapp.com/attachments/326138757474680852/729353592754012210/180738241824030720.png should not hold up
the section formula holds up (as expected), so this leads me to believe the formula the book provides is either a fluke (which I doubt), or some weird formula based off it
@steep temple
They are rewriting the formula
the thing you posted is relevant to your problem
i see it now
brushing up on trig and wondering how he just changed inverse tangent into inverse sin?
can anyone help me with some 30-60-90 and 45-45-90 triangle questions
@zinc pulsar
That's what the triangle in the top right is for.
Both tan^-1(3/5) and sin^-1(3/√34) represent the angle at the base of the triangle, and so must be equal
This is a common method that can turn any inverse trig into any other inverse trig
is angle 3 and 1 the same?
yes
since those two lines are parallel
you can take angle 1 to be equal to the complementary angle of 2
which is the opposite angle of 3 (thus, equal to 3)
thank you
for part A, first and foremost you write down the equation that says "these two angles add up to 180°"
only after that should you do any algebra to it
So ill put 6x+(9x+30)=180 for A?
How do I find the measures for part B?
well a good first step would be finding the value of x wouldn't it

@arctic vortex Yea I can
Just ask
Just send question.
,rotate
oh yeah sorry about that
okay
Shit idk how to give a hint without giving the answer.
Okay.
AEB is similar to ECD.
🙂
guys, how is tan 1 > tan 2
And what would be the apporach to compare in such questions
I still don't understand why tan 1 > tan 2, sorry if this is a dumb question to ask
you are working in radians
consider the inequality above
2 (radians) is in quadrant 2 (where tan is negative)
1 (radians) is in quadrant 1 (where tan is positive)
Oh! Thanks..that made it clear
which is enough to conclude that tan(1) > tan(2)
Thanks!
Can someone draw this out for me or explain it? I don’t understand it
try putting in acos(10/12).
I got it nvm
4 = x * tan(50°), so x = ?
are you able to solve this linear equation for x
or do i need to divide both sides by tan(50°) for you
ok first off what the fuck are you even doing raising the tangent function to the fiftieth power
i mean exactly what i said. why is tan not only being raised to the fiftieth power but also given no input?
and second, $4 = x \tan(50\dg)$ is an \textbf{equation} in $x$. why are you refusing to \textbf{solve} this equation for $x$ and only \textbf{then} plug the result into the calculator?
Ann:
i mean exactly what i said.
$4 = x \tan(50\dg)$ is an \textbf{equation} in $x$. why are you refusing to \textbf{solve} this equation for $x$ and only \textbf{then} plug the result into the calculator?
Ann:
how do i solve that equation
are you able to solve this linear equation for x
or do i need to divide both sides by tan(50°) for you
congratulations, you've done what i (indirectly) asked you to.
are you sure you're familiar with this calculator's syntax enough to be certain you're not entering the calculation incorrectly?
,w 4/tan(50°)
you rounded incorrectly.
you were told to round to the nearest tenth, not the nearest hundredth.
well which is it
3.3
which way do you round on a five?
yes
yay thanks
u are a genius
yesss i got another one right
@dark sparrow how do i do sin(53)=x/5
this problem
oh
i solved it
i got only 1 wrong
out of 10 questions
yess my homework is complete
actually now ait
i have 1 more packet
and then i am done yay
@dark sparrow how to do this?
make a diagram with only the relevant geometry and give some names to things
@dark sparrow how do i put tan^-1(203/1058) on calculator
your calculator calls inverse trig functions asin, acos and atan.
is this an "i don't know how to use the calculator" again?
ohhhhh
so its asin
ok thanks
i meant atan
@dark sparrow idk how to use the calculator again
tan45=253/x
for that particular equation, you don't even need one
unless you don't know what tan(45°) is
which you absofuckinglutely should
it sounds like you're psyching yourself up too much honestly
do what
$a=\frac{b}{c}$ if it were to isolate c, would you be able to do it?
Al𝟛dium:
but it says undefinted whe nput nto calculate
for that particular equation, you don't even need one
unless you don't know what tan(45°) is
which you absofuckinglutely should
idk why you're turning a blind eye to tan(45°) = 1.
Ill just dip
exactly the same way as all the other equations you've been throwing at me.
maybe just for a moment you should read AND UNDERSTAND what i'm trying to tell you.
but i dont understnad
then go back and review linear equations
if you posted a problem of it, we could help, we aren't in your mind
This question isn't too hard tbh.
Well, can you see that 2 is the radius of the semicircle?
So, what length does XZ have?
Yes, so it's an equilateral triangle
So what does that say about the angles?
Because the sum of all angles in the triangle is pi. So, the three angles are equal. 3x = pi, where x is just one of those angles
Hence, x = pi/3
No, the sum of the angles in a triangle is 180
or pi radians

