#geometry-and-trigonometry
1 messages · Page 266 of 1
DSpider do you understand what im trying to do
I set up a meeting with my math teacher at 10:30 so I’ll be getting help
when is that
45 mins
I got 14^2 = (16-d)^2 + 14^2 - (16-d)^2
Uhh
Area = 1/2 * a * b
Area = 1/2 * base * height
(for triangles)
yeahhhh
Guys, I can't imagine what is radical position, what is the difference between radical and tangential?
do you mean radial
Yeah
i dont even know m8
there should've been a little square marking it if it was
angle ACB is definitely a right angle
im just gonna assume theres a right angle
actually i think ican use pythagoras and secant tangent
well, you know AC = 8 and AB (which is the hypothenuse) = 10
you dont need to assume anythin since CPA is 90 (AC is a diameter and P a point on the circle) and APB are collinear
for the second one, call the centre O
then ABO are collinear
draw riht trianle OBC (or OBD doesnt matter by symmetry)
see what you get from there
what is special about it
a circle is the set of points the same distance away from the centre
that distance is the radius
so how do i find that distance
the important thing is that CO is the radius
r
so substitute that in to ur formula and solve for r
do you see how its the radius?
yea ok its the radius, but is the equation im kinda lost
baby pluto I thought we went over this 3 days ago
The perpendicular bisector of a chord passes through the center of the circle
and you obtain the equation (r-4)^2+12^2=r^2
r=radius of the circle
so how do you do that equation?
Pythagorean theorem
im confused
You have to draw the picture on paper
You will not be able to understand it if you just look at what I am writing
yea i did draw it on paper
just know a perpendicular bisector bisects the line into two equal pieces at a right angle
and the perpendicular bisector of any chord passes through the center of the circle
show me what you drew
CBC is a right triangle
so you can apply the pythagorean theorem
You did it correctly
Can i get help on ym math
put it in brackets though
my*
Find the length of the arc indicated in bold. Round your answer to the nearest tenth.
help
@acoustic jungle so i put the thing into teh calculator, but it became r^2−8r+160=r^2
how did 12^2 go to 160
@upper karma Thanks! I just got off my meeting with my teacher!
@austere terrace and was I right?
@pastel anchor (r-4)^2 =r^2-8r+16,
Yeah
16 + 12^2 =160
where did u get the 16 @runic peak
From the (r-4)^2
@rose oracle product of the radius and radian of the angle =10yd×30degree×pi/180degree=5×pi/3=5,2yd
all of them?
@rose oracle I think the answer is 12 120, but I'm not 100% sure
consider connecting some points and applying something like the inscribed angle theorem @upper karma
@rose oracle theta = s/r
again, not 100% sure about this, but it's plausible
Hey guys, if the radius of the circle is 5 and AB is 6, then the area of triangle is 25 right?
if AC is a diameter,yes
Ok, just making sure!
No, it would be 24
How?
@gentle hollow
He probably thought BD is the altitude
BD is not the altitude
Unless it's a isosceles
which it isn't
Wait a mỉnutes, guys, please explain to me what is racial position?
racial?
Radial
i think its the angle made by two radii
@gentle hollow is angle ABC a right angle?
there's no marking to indicate that it is
@upper karma it has to be
how do you figure?
since it is the inscribed angle that intersects an arc with measure 180
and incribed angles have 1/2 the measure of the arc
Or you can say: if a triangle is inscribed in a circle such that one side of that triangle is a diameter of the circle, then the angle of the triangle that is opposite the diameter is a right angle.
This wording
I just (re)learned what inscribed angles are 🙂 thank you
@gentle hollow
sorry about the poorly drawn circle 😛
angle ABC is indeed a 90 degree angle
Pretty good drawing
@pastel anchor
thanks
yeah what theorem is that
because it said BE = CD
yeah, I cropped it out
where are the letters on the corners of the triangle? 🙂
^Great start
?? i have it labeled on my paper already
eh, even without the labels...
Well what are you doing in class rn
like which unit this is from?
my geometry teacher is scary
well have you drawn everything
yes
@upper karma
- is ... 🙂
something, something, tangent
arc BA is twice angle CAB
arc BA?
oh?
doesn't look like an inscribed angle
well the thing is idk how to do it at all
my teacher never teached this
ty 4 the help
ignore that work
arc BA is twice angle CAB
@upper karma
it's not called an inscribed angle, is it?
no
but its still true
i think i just started learning this
after learning the arcs and secant
I know that angle CAB is a supplementary angle to BAD (both form 180 degrees)
yes
draw the radii
connecting to B and A
180 - 74 = 106. So angle BAD is 106. And if you say that it's twice the angle... that means arch BEA = 2 * 106 = 212
correct?
yes
i have
but, i'm struggling
yes
@upper karma
consider constructing RQ and/or PS
there you go then, @upper karma answer to 3. is 212
but...
2 * 74 = 148
2 * 106 = 212
148 + 212 = 360 degrees
can u help me by step by step
the question itself doesn't make sense
@upper karma with 3. ?
with 1-4
ok, what didn't you get?
the first one
do you know what an inscribed angle is?
(I just re-learned this myself today)
an inscribed angle is an angle with its vertex on the circle
For a complete lesson on inscribed angles, go to http://www.MathHelp.com - 1000+ online math lessons featuring a personal math teacher inside every lesson! In this lesson, students learn the definition of an inscribed angle, and that the measure of an inscribed angle is equal ...
"X" = "angle QTS" in your question 1.
"X" = half the measure of the arc
if you multiply something by 1/2 (or 0.5), you get half
i get it now
but how do u do numb 3
its different
from the rest
@upper karma said it's twice
scroll up
ok
BEA is twice of BAD so its 212
we got more questions
that needs helps
what is going on
geometer question
@upper karma you don't expect us to do all your homework, do you?
no
just need adive
on 5-6
you learned what inscribed angles are, so give it a shot yourself, see where you get stuck, then ask for help
@upper karma your answer for 1 is incorrect
Yeah I thought so too
why did you think that would work?
because you applied the wrong theorem
^
its just arc and angles
did you ignore that stuff and do it properly papi?
@upper karma https://www.youtube.com/watch?v=GppOSNTi5OA
This geometry video tutorial provides a basic introduction into circle theorems. It contains plenty of examples and practice problems.
Here is a list of topics:
- If a radius is perpendicular to a chord, it bisects the chord into two congruent segments. The point of conta...
yeah it seemed little wrong
that being said all the answers from 1-4 are wrong
I guess except for 3 because he didn't do that one
for 4 you didn't even use the other angle provided by the question
It's okay though
4 is a bit tricky
🍉
q3 had same bad notation.
minor and major aren't needed if you label your arc with 3 letters
and it doesn't make sense to call it minor especially since it takes up the majority of the circumference
at 2. it says that arc GI = 76 degrees, but angle GKI = 55 degrees?
yes
but the video posted by Fishraider at 4:45 says otherwise
"angle ABC and arc AC have the same measure"
K isnt the centre of that circle
it's good to prove the theorems so you don't accidentally misuse them
I think something is wrong with 5
I am not sure how to solve it unless it states those are tangent lines
in circle geo its a reasonable assumption that things that look like tangents are tangents
also only 1 point is labelled at each contact
It could be a secant line that doesn't extend beyond that point
but I see what you mean
the formula for 5. seems to be at 16:37 from the video above
if arc HF = 97, then arc HIF = 360 - 97
so angle FGH = 1/2 * ((360-97) - 97)
Yeah
That is still using the fact that they are tangent
and you could've also done it by drawing the right triangles and getting FGH+HF=180
Would somebody be able to explain how one would determine the angle of A for range of 180 < A < 360 where : sec A = 2
do you know the definition of sec?
^
I don't understand any of this honestly. Never did it anytime before now
if you don't know definition, consider looking it up
Been looking up stuff related but now really sure what you mean by definition honestly
tell me what you know about (the trig function) sec
It's something like the inverse of cosine where it's equal to 1/cos(theta) where 1 is the hypotenuse or something.
Most calculators and libraries don't have functions for it. Beyond that I'm not entirely sure about much
be careful with the use of "inverse"
reciprocal
it is the multiplicative inverse.
reciprocal function (of cos) works too
so for your question you can rewrite it as:
$\frac{1}{\cos(A)} = 2$
ramonov:
So, doesn't this just change the difficulty from sec to cos as A is unknown so I can't use the cos function on it
perhaps if i then rearranged it to
Geometry is awesome 👍
$\cos(A) = \frac12$
ramonov:
would you be able to determine the possible values of A
From what I know of math wouldn't it be 2*1 since whatever you do to one side you do to the other?
wouldn't what be 2*1?
cos(A) = 2*1
I don't even know anymore. This stuff hurts my brain trying to figure out.
i took the reciprocal of both sides to get cos(A) = 1/2
multiplying both sides by cos(A)/2 would've achieved the same result
I feel like there's information I'm completely missing or my brain has just melted. So sec A = 2 turns into the reciprocal of 1/cos(A) = 2, what the importance of moving the 1 over to the other side?
wdym by moving 1 to the other side
moving from above cos to above the 2
the idea is to rearrange it to a form that you should be familar with
that's cos(A) = 1/2
is something that you shouldn't have too much trouble solving
I'm familiar with exactly 0% of trigonometry. I apparently should have done it in high school but it was never covered.
and if you can't then you pretty much have to start trig from the very beginning
try khan to get the basics
khan?
khanacademy
I love khan academy 👍
I'll have to look into that later, don't got enough time to properly learn this stuff at this time
Good website! And it’s free 👍
I don't know if I'm putting this in the right chat, but i need someone to tell me if i did this right. I think this is supposed to calculate the size of the triangle or something like that... I'm not good at maths but the Points are A(-2,1) B(3,2) C(4,-5) thanks in advance
@upper karma it's not very clear what the problem is
logically speaking, why do they h and k also get flipped when the x and y do
it becomes y-k
@upper karma "Size of triangle" ? Do you mean area? Use the shoelace theorem
it's fine i asked a classmate and he said it's correct so
@unborn jacinth well now you are looking at the graph in respective to x, so the values are flipped
It is not easy to explain
also it wasn't clear what the problem was to me either since i missed out on 2 weeks since no one told me we were having online classes
ok
Maybe it's because 1/4p is unnecessary here
like consider rotating the graph 180 degrees
then "subbing" y for x if that makes any sense
Wait a second, it doesn't make sense
@unborn jacinth those equations shouldn't be equal
also I just realized I meant to say 90 degrees not 180
oh ok
can anyone help me with some of my geometry hw?
Okay I don't even know if this is trig.
Convert 98 degrees 51 ' 16 " to an angle in decimal degrees.
What even is this?
okay
How is that a unit of measurement? I can't even.
@steep marsh Google it perhaps?
i did
i have 3 other ones that far
i googled asked my friends and tried to solve it by plugging it in with these formulas
okay thank you
eh
ok
so basically
let x be the radius
therefore the slant height is 3x
do you follow so far
yes
for the question?
just in general
whats the formula
to finding the surface area of a cone
Im asking you so I can make sure you understand
oh its the lateral plus the radius squared x pie
yes
yes
what is LHS?
Left hand side
oh
gimme a sec
ok
okay
yes
yes
4r^2
square root
give a guess even if youre not sure
2=12
nope
divide both sides by 4 first
you have to isolate the r
actually
you know
square root would work
but traditionally dividing by 4 comes first
ok lets do it your way
okay
2r = 12
we have more tho
yes
i will if i need to
Yes 👍
thank you @little osprey
no worries
GUYS! can i turn r=2cosθ into rectangular coordinates
idk
Fr?
@simple slate problem is too blurry
@keen nexus just do Pythagorean theorem
pinged the wrong person there buddy
@simple slate
Maybe idk
What’s that 54
Ya just do Pythagorean theorem I think since it’s a kite or rhombus
And diagonals of a kite are perpendicular
Your welcome
GUYS! can i turn r=2cosθ into rectangular coordinates
Start by thinking how do you express r in terms of x and y?
and then how do you express θ in terms of x and y
then just plop that in and you should be good to go
so its the same as a rectangular equation
Forget i said that
I keep failing on this question can someone help me
is the base a regular hexagon?
yes i believe so
i don't get why they felt the need to specify the height to the middle you can calculate that
Do you know how to calculate the area of one of the triangles of the pyramid
I tried to view the example they give but I feel like the y skip a step
Wouldnt it just be the base x height /2
You see that all the triangles of the pyramid are identical
and that the base of them is 22m each and the height is also 22m
so what's the total area of the triangles?
1452?
how do i solve for the area of a hexagon
Yes I did
now do you know the height and the base of one of these triangles?
the height is?
how do we figure out the height?
Oh is it 11 rad 3
yeah so now do the same thing you did for the triangles before but with these measures
is it 726 rad 3
ok so do we need to multiply that by rad 3
do you have a calculator on hand to approximate that
yes
what does it come out to?
1257.468888629....
so now add it to the original
which was 1452
and then round and that should be your answer
2709
now is that the correct answer?
good luck if there is more questions :)
thanks
are* 
naw bruh 😂
is this geometry
Pony Boy:
hey mate try not to ping specific members, but yes
Oh I'm sorry Sneaky
so what's the trouble you're having with this question?
Okay part A is my problem with converting the W
so we have V=3i-j
and W=4i+sqrt(3)j
we want V-W
so we have 3i-j-(4i+sqrt(3)j)
do you agree so far?
we group and we have (3-4)i +(-1j-sqrt(3))j
ya
so thats -i-(1+sqrt(3))j
sometimes it may be appropriate to convert that to a decimal
Okay so I can't do anything with that sqrt part
Are you talking about the sqrt part?
Okay
and it will make your job easier on the questions finding the magnitude
If I dont?
then you bracket 1+sqrt(3)
yes
because you're gonna have to square it later
is why i said you shouldnt turn to decimal
(in d when calculating the magnitude)
Okay D is the other part I was stuck on
sure, what was your trouble?
sure
heyy
5 degrees?
Okay
Yes
Okay
Pony Boy:
That's what I'm aiming for right?
Not nessecarily, no
Oh
I'm trying to think where I'm messing up then.
Dont I use the answer from part a for part d?
You have the i and j components for v-w, so do the same thing you did to get magnitude for w
Nope
Pony Boy:
So something like this
Yeah I'm not either, kinda hard on the phone lol
Also, we usually dont write the is and js under the sqrt
Oh
I don't think you'd square the i and the j
What happens to a negative number when we square it?
Sir you're right, but i already corrected him on that
Also, we usually dont write the is and js under the sqrt
@versed river
Sir you're right, but i already corrected him on that
sorry, I had a lot of lag and didn't see that
Yes like (-2)^2
Imaginary numbers are an expression for the square root of negative numbers
Yes
Sorry I was thinking sqrt
So what im getting at is you can rewrite that without negatives so you can solve it without a calculator
Although looking at it more you may still need a calculator
Like the length of an arc of a circle?
you can determine what fraction of the circle it is and then find the formula and multiply it by that fraction
So it would just be $\sqrt{1+(1+\sqrt{3})^2}$
binomial theorem
like, I'm doing a math test online and it shows the measure of the arc is 135 but then it says calculate the linear measure and says "PQ = _" but somehow I have to have pi in the answer
The 1 +root3 would be squared but yeah
But the negative wont cancel it?
Assuming the measure 135 means degrees find it as a fraction of the circumfrence
how
Pony Boy:
Can I simplify the 1 out of the sqrt?
You most defibitely cannot
135 degrees is what fraction of a full circle
So that would be the final answer? Seems like I did something wrong
When it comes to the squaring the negative
or pascal's triangle
$\sqrt{(-1)^2+(-(1+\sqrt{3})^2})=\sqrt{1+(1+\sqrt{3})^2}$
I'm confused now
Yes
then just plug in a = -1, and b = -sqrt(3)
a^2+ab+b^2
indeed
Sneaky:
what he's getting at is that theyre equal
Okay so the answer is
and that you can expand with or without making the simplification that its positive and get the same answer
$\sqrt{5+\sqrt{3}}$
Pony Boy:
Hmm
i think 5 is pretty correct
I forgot about the other 1
Oh cool
but you're missing something, i believe
it's 2ab
$\sqrt{1+(1+\sqrt{3})^2}=\sqrt{1+1+2\sqrt{3}+3}$
Ohhh
where is my tex

Sneaky:
2ab I forgot
so thats actually $\sqrt{5+2\sqrt{3}}$
Sneaky:
there we go
Okay cool
that all?
I have a lot more but I'm going to try and figure them out again
This is helping me a lot with understanding vectors
Thank you
sir i'll let you answer since you're typing
Still answering one sec
okay
(-3i)+(-5j)
bruh you got it
Yes!
oh wait
wait, isn't it 3, and 5
Lol
i misread which one was which point
Positive?
yep
isnt it positive?
Why is it positive?
you subtract initial from terminal, I think you just got them switched up
So its 3i+5j?
indeed
yes. draw a diagram to conceptualise this if you aren't sure
it's positive becuz it's an increase of those values
Ohhh
not decrease
ye because the terminal values are greater than the initial
@compact spire You can do it! I believe in you! We all do! 👍
lello?
hello
cani ask questions here?
indeed you can
trigo-related
yessir
I'm sorry, I can't see the question
i sent it through pic
I can't see the question in the pic I mean
- In triangle RST, the measurment of angle RST is 60, and ST is 8, find RS
yes
these:
well, you can use those to find cos(60) = 1/2
then you just multiply 1/2*8
oh its 1 half because the measurement is 60?
ye, because we want cos of 60
anyone know how to do my question?
that looks like a quiz on canvas
cos(60)=1/2*8 = RS?
indeed
nice
its called online school
yes
I think I figured out my problem 🙂
nice!
yeah I had to redraw my diagram
what was your final diagram?
ill post a picture of part a and b, need me to repost the question too?
I've got the question
Okay
@remote heart what do i use to find ST if ever i want to?
this shows as false in photomath
no 8?
but you said you had 8*cos(60)
nice!
I got it good right!?
I believe so
Cool
Okay im having trouble with this next problem because I dont remember how to calculate it properly
Okay so I have this so far which I believe is correct
not sure if you can read it
ye
I think I might know how to calculate it if its the same as part d from earlier
where I just sqrt it all and square the v1 and v2
is there a target?
okay
$\sqrt{(2509.4)^2+(1312.1)^2$
Pony Boy:
Compile Error! Click the
reaction for details. (You may edit your message)
I was at $ <1000(cos(0)+2000(cos(41)),1000(sin(0))+2000(sin(41))>$
Pony Boy:
and I narrowed it down to $<2509.4,1312.1>$
Pony Boy:
$||v1+v2|| = \sqrt{(2509.4)^2+(1312.1)^2$
Pony Boy:
Compile Error! Click the
reaction for details. (You may edit your message)
just a sec
Okay
isn't it asking for the horizontal force on the stump?
Pony Boy:
$\mathrm{you, didn't, really, need, to, type, that, out, in, latex}$
lul
AMD:
$💩$
@compact spire I think to solve that problem you would find the i components of each one and then add them together, no?
how do you mean?
you know how you can visualize vectors using graphs?
Okay
the i component would just be the change in x
Okay
41 and 90
yesyes
I'm not too sure how to describe this, but we want to find the leg that coincides with the x axis
the leg adjacent to the 41 degree angle
so the opposite
yes
The volume of a pyramid is 50 cubic units. The base is a square with sides of length 5. What is the height?
how do i solve
what are you stuck on?
can I use the form Side-Angle-Side?
idk how to start it should i use volume equation for pyramid?
side-angle-angle, I believe
yes
yes, yk
recall the volume of a pyramid
2000lbs(hyp)-41deg(theta)-90deg
ye
A cone and a cylinder have the same radius and height. The volume of the cone is
100 ∏
cubic feet. What is the volume of the cylinder? Round your answer to the nearest tenth.
how do i start this
do you know the relation between a cone's volume and a cylinder's?
v=pier2h ?
no, their relationship
^
nope
go on mister
do you know the formula for the volume of a cone, or the area for the volume of a cylinder?
yeah
v= pie r2 h
compare the two formulas, what relationship do u see?
pie r2 h
pie
no, i meant relationship
yes, but in the cone it's being multiplied by what?
1/3
indeed
so 1/3 x 100?
100 is the volume of the cone
you're trying to find the volume of cylinder
substract 1/3 from 100?
why subtract?
@compact spire taken atm
use a #❓how-to-get-help channel
indeed, 100/(1/3)
hey guys i have a question, so i have this example and i can't really find the way to get the answer with my calculator
I'm trying to get that -0.893
Idk what i'm doing wrong
I'm following the formula.
The main question is about 2 forces that lie on 1 point A
what are you trying to solve for in the end?
I'm trying to find the angle between two forces
so angle abc
no.
set AC=1012, AB to 567...
That is what i did, but i get an error.
Result:
-0.89288231148696
cos is a function. you cannot get rid of that by division.
watch me
@prime jewel so you got cos (abc) = somehting. you want only (abc) in the end. remember what you do then?
A pyramid has a height of 4 inches and a volume of 40 cubic inches. Circle all figures that could be the base for this pyramid.
a 5 inch by 2 inch rectangle
a 3 inch by 10 inch rectangle
a heart with area 30 square inches
a right triangle with one side 5 inches and the hypotenuse 13 inches
a triangle with height 10 inches and base 3 inches
arccosine lul
taken, post in a questions channel
How would you go into the problem, you replace the Terms, and then you solve, you square it and you move all terms to the left
and then arccosine.
But when i do it i get an error
oof
what's the error?
Could you pop into a channel so i can explain?
Anyone?
I'm on Mathematics voice channel rn.
no voice here 😦
Youre backkkkkk
I know that it’s 2pi/b
the period is just when it returns to the starting value
Yeah man. Thanks to sneaky I passed my test with a 98/100
Amp is not -3
da
yeah no we all make mistakes
just a happy accident
frequency
Is it pi/4
Imma let Mistersir handle this
it'll be confusing if both of us type over each other
So is B pi/4?
y has not yet been > 0 at pi/4
full circle 🤔
so a full cycle
@remote heart
at 3pi/8 y isn't 0
Wth
full circle 🤔
@remote heart
@wary bone
guess both work 😄
it says full cycle?
yes!
hmm, so why at pi/2 it is considered to be a full cycle
because at pi/2 y has already been > 0 and < 0 and at pi/2 it is 0
so it has returned to it's original value
I see
and been greater and less than zero
Its had one maximum and minimum value done and came back to the principle axis
gonna screen shot this so i dont forget
you can look at the distance between two maximums aswell. or two minimums.
oh yea
also to get the period, we do : 2pi/(pi/2)
yeah because the default period would be 2pi, have to adapt to that
da
are you Russian by any chance mister
nyet
Ukrainian?
can you help me FIND an exercise?
i need a real life example of any circle, where you know the surface area but not the radius. (i only find ideas where you know/measure the radius first)
a circular kiddie pool covered in water?
but just the surface
no, that's a bad example
So guys is the graphs equation come out to f(x)= -5sin(4x)