#geometry-and-trigonometry
1 messages · Page 11 of 1
yes
ye
Area of the Circle= pi r^2= pi*5^2 which is approx. 78.53982 (round it accordingly)
I think it’s just asking for the exact answer so I can keep it in pi form
alr!
in a rectangle, the base is twice as long as the height. calculate the area of the rectangle if the diagonal is √215 cm.
Can someone tell me how to solve this question??
represent the base and height in terms of the same variable
Here I drew you a model
Use Pythagoras to determine x
what do they mean by this
Trig is used all over the place where angles are involved, not necessarily only when triangles are involved
ah thanks
Prove CU x CV=DU x DV where U and V are the circumcenters of AOC and BOD respectively
is there some sort of list for theorems abt circles
https://thirdspacelearning.com/gcse-maths/geometry-and-measure/circle-theorems/ found this. It might help
Oh ok, I can't help prove them sty
its ok
Guys so like if I'm evaluating functions and like it gets to cos(-1) like then what
Cus tbh my trig is not great and like I just keep getting messy decimals and no good values or anything
Unless I'm being really dumb and it's pi but I'm pretty sure that's not how trig works
How far u have done with this ques?
Use the cosine rule
Find X?
1610sin(67°)
help pls
Start off with y= tan x
You can see that the graph is translated pi/4 to the right first, so we now have y = tan (x - pi/4).
From here, we check for at least one point:
E.g. when x = pi/2, the y-coordinate should be 3. As tan (pi/2 - pi/4) = 1, we need to multiply this equation by three to stretch it parallel to the y-axis, and get the desired equation y = 3 tan (x-pi/4)
"Prove that if a plane is perpendicular to two secant planes, then it is
perpendicular to the intersection of these planes."
help pls
You can try doing the cross product of the planes' normal vectors first
Not entirely sure but that's something you could try
hello. im not sure if i can post this question because its in calculus. but basically im trying to solve a question that deals with arctan and the limit as "a" is approaching -infinity of arctan(a). should i look at the tan(x)'s domain to justify the behavior of arctan?
Seems like a reasonable step, but just be careful to justify, since tan(x) has the domain over all the reals, whereas the domain of tan(x) is restricted to define arctan(x) as a function, such that it's range is (-pi/2, pi/2).
Since we're in geometry chat, you could also consider, if you had a right-angled triangle, and one of the acute angles has fixed adjacent side, but an opposite side which has its length approaching infinity...
Seems kind of wishy washy, but it seems like as if the angle gets closer to pi/2.
thank you for explaining. that's what i was worried about, getting confused with the domain. ok just so im clear completely, tan(x) is only restricted to define arctan(x) from -pi/2 to +pi/2, so the limit would only exist between -pi/2 and +pi/2?
That would probably be fine, so long as you keep domains/ranges clear for each function, and don't get mixed up between the two :)
ok great thanks for helping 
Can someone explain the operations on deriving half angle identifies from the Euler formula
my tutor showed me the formula for if I forgot my identities
I kinda forgot how he even started it 🥲
I’m in precalc 2 btw if that’s necessary information
What is the given informations
There are at least 9 things named “Euler’s formula”
You may want to look at this too
In mathematics and physics, many topics are named in honor of Swiss mathematician Leonhard Euler (1707–1783), who made many important discoveries and innovations. Many of these items named after Euler include their own unique function, equation, formula, identity, number (single or sequence), or other mathematical entity. Many of these entities ...
the things i sent are all the info i have
I think the sum is 180 degrees
You just have a star right ?
a random pentagram with nothing specified
lemme try
Lemme upload pic
@warm canopy
thank you!!
...you literally asked them if it was asking for angle sum and it wasnt tho
tho honestly that's the only reasonable thing that would be asked
wait which angle is which and where did the A’ B’ C’ D’ E’ come from are those the interior angles of the polygons
I meant this one
how do i solve this?
Doesn't your textbook explain how to find the distance between points in a coordinate system?
it does
i think'
but i dont have it on me rn
soo
its a formula
but i didnt memorise it
You might have to rederive it, then. Draw a hoizontal line through one of the points and a vertical line though the other. Together with the line connecting your two points, they form a triangle with one right angle. Apply the most famous theorem about right triangles you remember.
... or you could also use what Daht posted and lose the learning opportunity.
My bad
is there things like
uh
like you have $\sin \theta = \frac{a}{b}$ and then $\sin^2 \theta = \frac{a^2}{b^2}$, is there such a thing as eg. $\arcsin^2$?
There's not a particular name for it, no.
In some situations it can be useful to know that (by trigonometric identities about squared sines) we do have $$\sin^{-1}\sqrt x = \frac{cos^{-1}(1-2x)}{2}$$
Troposphere
You could use the pythagorean theorem or the distance formula
if i drew this correctly, line AB is hypotenuse right?
Hello! I have a question about proofs. I learned that proofs are usually written using table of statements and reasons, and every small step should have a reason (name of some property, not just explanation). I find this way very long and exhausting. Are there other ways to write proofs and solutions in geometry?
you learned that 2-col proofs were the "usual" format?
cause yeah thats bureaucratic as shit and tiring to stick to
usually a porof is just plain-english prose maybe interspersed with some calculation
So usual "non-bureaucratic" proof is just explanations in words and some calculations when needed?
yes, essentially.
two col is excessive in the need to explicitly state "given" and trivial theorems
which yeh, can be exhausting, there's no real need to have all that
Yes.
I think "two-column" proofs could make some sense if they were taught as a scratchwork technique for making sure you have all your ducks in a row before you start writing out the human-readable proof. But they're likely harmful if they become a homework objective in and of themselves.
Thanks!
yo hello can anyone help with my homework? trig
@everyone does anyone know about pythagoras theorem?
Nobody knows about Pythagoras' theorem; the last surviving description of it was lost when the Great Library of Alexandria was sacked.
I think you're talking about arithmetic, Pythagoras theorem is actually described in the Bible
Okay
how do I know if my foci is parallel to the y-axis or the x-axis?
im wondering if its related to the semi-major, but im not quite certain
The foci of an allipse always lie on the major axis.
is there any reasoning behind this being ex. sin(v+pi) and not sin(v ±pi)?
ok, where a is greatest, that's where the focal is?
since semimajor = the a component
So I'm assuming you're asking about the focal point of an ellipse, which is one of the two points that define the major axis of the ellipse.
In an ellipse, the distance between the center and each of the two foci is denoted by c, and the distance between the center and each vertex (i.e., the endpoints of the major axis) is denoted by a. The semi-major axis of the ellipse is then given by a, and the semi-minor axis is given by b, where b = sqrt(a^2 - c^2).
So to answer your question, no, the location of the focal point(s) is not determined solely by the value of a. The location of the focal point(s) depends on the values of both a and c, as well as the position and orientation of the ellipse.
However, it is true that the value of a is related to the length of the major axis of the ellipse, and therefore to the distance between the two vertices. Specifically, the length of the major axis is given by 2a.
i was asking more so about the foci's relationship to the y-axis versus the x-axis. because sometimes you need to use different equations for the same problem
@tender token
is it just the semimajor that decides?
sorry if im asking the same thing after you explained but i dont really understand ellipses
What would the points of my own geometrical algebra equation be? I used such 2 + 2 = 2x (squared (2)) which both sides of a square is 2 it converts into a cube which is entered into cube = 2x (squared (2))?
Summary: Square (both sides are 2) = 2x² = Cube 2x²
My whole class strugglin need som help
!nosols
As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.
"find the length of the unknown sides of this right trapezoid, and find the area of the trapezoid"
im struggling with this problem
not sure what i did wrong here, deltamath says im wrong
nevermind i figured it out
👌
I need help
Can u do this question
Help
Ignore the writing around it can you help with that question tho
do you still need help
for the bonus (29) use Heron's formula to solve ((1/2)(a+b+c))=s then sqrt(s)(s-a)(s-b)(s-c)
for #25 use law of sines to find angle z, then use angle sum theorem to find angle y
I've drawn a few more lines -- red is horizontal and green is parallel to the inclined plane so the angle between red and green is the angle of the ramp.
Now red is perpendicular to black, and green is perpendicular to dashed blue.
the only way I could think of rn, is by finding the opposide side to angle 25 (you'd need a calculator), then it should be easy.
you can figure out the sides easy with the trigonometric rules of right angled triangles. Is thr problem figuring out the area of a triangle?
b
what can you do to that angle that gives you some insight to the sides?
with these trigonometric rules you can figure out the sides if the triangle
you may also use law sine for the oblique trianglge
indeed
Ups here B & C are the centre of the two circles
Since radius 2
AB = BC = AC = 2
so according to the tringle being equilateral
angleABC = angleACB = angleBAC = 60degrees
so [ABC circular cut] = theta/360 * pier^2
= 60/360 pie * 2^2
= 1/6 * pie * 4
= 2pie/3
and [tringleABC] = rootover3 a^2/4
= rootover3 * 4/4
= rootover 3
so [black region under ABC circular cut] = 2pie/3 - rootover 3
= 2pie - 3rootover3/3
So the other one is also 2pie - 3rootover3/3
And the down black region can be divided with the tringle where it creates the same situation like the upper one
So there should be 2 other black region under circular cut with same area
So all black regions under circular cut are 4
[all black regions under circular cut] = 4{(2pie - 3rootover3)/3}
= 8pie - 12rootover3/3
And the other same tringle (with same area) should also be added as the down black region except the 2 down black regions under circular cut
So the actual [black region] = 8pie - 12rootover3/3 +root3
= 8pie -12rootover3 + 3rootover3/3
= 8pie - 9rootover3/3
Hence,
8pie - 9rootover3 / 3 = apie - b rootover c/d
a = 8
b = 9
c = 3
d = 3
and gcd{8,9,3,3} = 1
So ( a + b + c + d) = 8 + 9 + 3 +3
= 23
{Ans?)
Am I right or not?
<@&286206848099549185>
THis ques
Isn’t ABC triangle equilateral
Yea
Well I have added a solution but not sure if this is correct or not plz help me <@&286206848099549185>
Hey anyone here studies Euclidean geometry
from all of the people that are in this server there is a very high chance that someone is or did
obc is 50 because ob bisects ac. so obc is 50 so u know bac. ob = oa so z = 50 - bac.
aob = 180 - oba - oab = 180 - 2*50 = 80;
bac + bca + abc = 180 ==> bac = (180 - abc )/2 ==> bac = 40
hello. just a question, is the definition of horizontal tranverse axis means that the parabola opens upwards and down?
can anyone help me with this one, i thought the answer was 82 but i guess not
OMG I'M LEARNING THIS, TOO
SOO FRIKIN HARD+EASY LMAO
just use this formula... m<1=(m of arc AB + m of arc CD)
(These are just random letters, you can do it accordingly for your problem)
he left oml
76= (82 + x)/2
76= 41 + x/2
x=70 {x: arc BC}
hello guys, i have a question. Idk if this is basic or advanced math too so i ask here
i saw this guys calculate circumcircle of a given triangle's coordinates with something called D. I have no idea what that is and how do this work
you may confuse by coding, but at the end he give result of the triangle circumcircle coordinate is:
(X / D, Y / D)
Hi, can someone help me with this one? We're supposed to find the area for the ones that are shaded.
assume 2 rectangle's edges is x and y, you calculate "7" and "5" based on x and y
and reversed the formular
Something like this?
yeah
i dont really remember any formula from high school, but there would be something to do with the angle
if you have 1 angle and 2 edge, you can calculate the other edge
Huh
you apply that formula to both triangle, you will have an equation
solve that equation you will have the answer
does that only applies for right triangles or not?
no, obs not
The angle is unknown in the problem however
Wait which one
Wait how do we find the 2 angles though, they clearly don't make a 90°
And how do we find the area after that 💀
You meant cosine rule
just use it on each triangle and hope that stuff cancel
A solution without trigonometry probably exists but is not very easy to find
The angles are supplementary; their cosines sum to 0
Huh
Fyi I was talking about this
Ah
It means $n$ is an integer, $\mathbb{Z}$ represents the set of integers
Civil Service Pigeon
It’s because you need to add integer multiples of the period
Cause otherwise, you could say stuff like $\sin(\pi/2)=\sin(\pi)$, which is clearly false.
Civil Service Pigeon
ty!
Pythagorean theorem
Probably the unit metres?
Such a tall building with only 3 floors
what i did so far was made 3x=a and then said 10(2sinacosa)=0
but im not sure where to go from there
What do you know about trigonometric functions?
Ik sin cosine and tangent and law of sine and law of cosine but I forgot how to implement the law of sine and cosine
law of sine right
since its an enclosed angle
For this problem it's more convenient to use tangent
You are given a side length that is opposite of the angle and adjacent to the angle
So, you'll have to use tan^-1 (30/8) to get the angle
ohhhhh
ok thank you that makes sense
I forgot abt the inverse ones
I was trying to write 8tan(x)=30
so 75.07 deg?
If they ask you to round to the nearest hundreds, then yes
Is there a clear formula to calculate volume?
Sry it was just unclear for me
Nvm sry got it
The formula varies by the shape
Not really sure how to explain this. I have a line to a point and a 3d vector from that point with an X and Y rotation. How can I find the angle between the line and the vector?
Can someone please tell me if 13 is right
I think I did it wrong but idk how else to do it😭
guys?
pls
i think arc YVU stands for the arc that starts from Y and goes counterclockwise around the circle until meeting U
are you trying to find the hypotnuse
yes
Use your trigonometric function rules
sin 31 = 16/x
Need help with these questions (last three especially) Thanks!!
area of triangle = ((ab/2)*sin(C)) where a and b are two side lengths and C is the angle between the sides. the answer is now just plug to calculator
You may also refer to Heron's formula as 3 sides are also given
use calculator for convenience
How do I prove that in a triangle the semi perimeter is always bigger than a side?
a late?
what have you tried?
its the semi perimeter
semi perimeter=(a+b+c)/2
Yeah I mean that
use lowercase notation instead of segment notation,
it'd be much easier to read
?
whats the equation?
brb
its just basically sorting the lengths in order for convenience
Is it fine if I subtract two egual sides in every part?
Oh never heard
But I can try it
Then I have to do another thing
It asks me another thing
and apply that to get more info about
s = (a+b+c)/2
Did I do it well?
backk
well your inequalities are just saying that double the perimeter is greater than the perimeter
which is trivially true
Yeah but
can u tell me the equation?
.
let me think ;-;
The sum of any two sides in a triangle is greater than the third side.
Let a b and c be the length of the three sides
So we have (a+b) >c
Adding c to both sides we bave
a+b+c > 2c
This implies (a+b+c)/2 > c
The LHS is semi- perimeter of a triangle.
So semi- perimeter of a triangle is greater than any side of the triangle.
Lmao you are a computer to write this in a second
its basically like
consider given
a <= b
then
if a = k
you can conclude that
b >= k
did you want greater than at least one side, or the longest side
I try to do the other part
Uhmm
?
Let me check
I'm Italian we don't have grade lmao
Year 11 for Uk
I looked only my age lol
15
What is csa
Oh
yeh
2 pie r h
Didn't do it yeah
For lateral you mean all the area without counting the bases right?
Oh k I did it
yeh ;-;
Yes
Not probability bcs I can't do nothing
Ok this yeah
yeh that kinda complicated but yeh
Btw I can't do the other part
which one?
How do I prove that in a triangle the semi perimeter is always bigger than the height ?
uh wait
I try it too
i thought u understood?
Oh got it
;-;
It's the height now
idk that ;-; let me try
yeah idk
ask someone from ur class
if they know it
Yeah lesgo
goodjob
I have mainly to start thinking on what it asks
I have another exercise I will see if I have problems
Thx for the help again
ur final exams?
happy to help
You mean to graduate to university?
yeh
I have to do another 4 years
So basically I go to university at 18 years
Yup
Maybe I think we have done like a melting pot of science in the last years ahaha
uh
Ok Lmao I didn't do tissues
help!
im so bad in bio
fr
i lost like 4 marks
forgot
we shouldnt curse
;-;
and the assertion and reason ong 💀
We've only did muscular and nervous but in general we didn't do biology. I can help you more in astronomy and chemistry
yeh chem
We've only studied the human body
Lmao at 14 you've already did these things? 💀
i have just memorised first 20 elements in the periodic table
uh yeahhh
Ok we have studied like 60
yeh
We'll doing these things the next year
Lmao
It's because the schools in the world aren't the same
Yeah we are here
yehh
so tell me what do u understand by it
homogeneous has like solutions
and heterogeneous is of 2 types
colloids and suspensions
have u studied about saturated ,un saturated and super saturated solutions?
I'm writing what I know about them lmao
Nop
Satured is like when you can't dissolve anything else
do u want me to give u a brief about it
so u can answer confidently in ur class when the q comes!
Lmao we are i the geometry part btw
what?
That we are in this channel
Where do you want but I will have to study astronomy and chimics for tomorrow test
okay study i dont wanna disturb ima do maths ig
or science
Good luck for your exam bud!
No problem
You can say it and I will see when I can
only 60 pages
🙂
Ok goodbye and thanks everyone
Then why r u doin maths go study that topics xD
I have homework for tomorrow
okay ig
I have even to do Olympics of Italian then 💀
byee all the best for tmrw
At least it's for Monday (the Olympics)
cos(x-pi) = cos(pi-x)
sin(x-pi) = -sin(pi-x)
this is correct?
yes
thanks ♥️
Can someone help me with this?
You know that a circle is 360 degrees
and 98 degrees is 40.62 in^2 in area
so make a proportion
Ah, I get it, Thx
can i get help on this (both perimeter and area)
firstly label all of the side lengths to make this easier
ok
after you do so, find the perimeter by adding all of the side lengths together
are these correct?
Yes
can the unit circle be used if the hypotenuse of a triangle is not 1
No because the unit circle has a radius of 1
so whats the point of it then
if it can only be used with a triangle that has a hypotenuse of one
Because the hypotenus = sqtrt(cos(x)²+sin(x)²)
You have a triangle defined by sinus and cosinus
what does that mean
you can use it with a traingle that has a hpyotenuse of anything?
I don't understand
If you take a point on the unit circle it is defined by a cosinus and sinus which bot have a value between -1 and 1 and if you use the pythagoras theorem with cos(x) and sin(x) you get the radius of the circle
So if you have a cosine you can get it's related sinuses
Thanks to the pythagoras theorem
what is a cosinus
Cos(x)
x is theta right
Yes the angle
ok so let me get this correct because i have a very basic understanding of the unit circle
the unit circle is used to find the x and y of a triangle when you have the angle right?
like sin is y and cos is x
Yes
so i just dont understand how it can be very useful if you can only use it to find the x and y values of a triangle where the hypotenuse is 1
unless im wrong about that
With a cosine you can find a sinus and vice-versa because the hypotenus is always 1 it's easy
ok but im still not understanding
What are you not understanding?
this
like what if the hypotenuse of my triangle is 34
Then you don't use the unit circle
but then why even use the unit circle
Because in trigonometry you have a circle and a triangle that are alike
so what im not understanding about this is the 1 being the hypotenuse
I guess
It has nothing to do with that. The unit circle has a radius of 1 unit because it is easier to work that way but you can really have ANY MEASURE OF RADIUS. Since, in reality, there the concept of RADIANS is at stake (which has to do with the relationship of a radius and the perimeter of the circumference). That said, those RADIANS are used to measure an angle (counterclockwise, from the x axis).
That angle determines a point on the circumference (in any of the four quadrants) and from there the cosine (abscissa of the point on the circumference) and the sine (the ordinate of the point) are defined.
i know why it is 1 because its the UNIT circle and 1 radian but im not getting why its that useful if you can only use it for a triangle with 1 as the hypotenuse
so can the unit circle be altered to be able to use 34 as the hypotenuse
I don't think so
but he said " but you can really have ANY MEASURE OF RADIUS. "
does e=mc2?
He said that it's easier to use 1 as a radius but you could tweak it to have any radius
yeah so why did u say i dont think so when the hypotenuse is the radius
and how would you tweak it to use and radius and therefore any hypotenuse
Because i personaly didn't learn any purporse for a unit circle to have a different radius than 1
Multiply cos(x) by the new radius as well as sin(x) i guess
What are you talking about
is that all you would have to do?
Yes, but you would have to change the measures of the angles (there is a formula, I think it is x/r) but just understanding the unit circle is enough. If you want, to understand better, looks for "the Euler function" that function associated to each real number an arc on the unit circle. From there, it can be expanded.
are these correct
perimeters are wrong
It is valid for all triangles. Remember that sinx and cosx are periodic functions which means they repeat values on a certain interval.
Think about a simple value like sin(30*), this evaluates to some ratio which is 1/2. Now let's use your aforementioned example of a hypotenuse of 37. By using the unit circle we know that a value of 30 degrees or pi/6 radians evaluates to 1/2 and this can be applied to any triangle.
Let's say that your triangle has sin(x) = 37/74, we know that x = pi/6 works because of the unit circle.
I hope this makes more sense @cedar grotto
This might be a dumb question, but how do you draw a triangle given it's name (∆abc for example) ?
And is ∆abc and ∆cab the same triangle or is it different?
usually capitals should be used for points
triangle ABC, is just a triangle with points,vertices A,B,C
you can have your A,B,C clockwise or anticlockwise, doesn't matter
well for a triangle it doesn't matter, it'll be in order no matter which way you arrange them
it can
well for a triangle it doesn't matter, it'll be in order no matter which way you arrange them
try as much as you can to screw it up
Now my second question
Do different names results to different triangles?
Given that both names share the same points
wdym
Like I said before
This
triangles ABC, ACB, BAC, BCA, CAB, CBA are all names for the same triangle
order doesn't matter
Okay then
if you're referencing just a lone triangle
if you're doing stuff with similarity/congruence then
you'd order the names based on corresponding points
That's what I'm doing
Finding the corresponding sides and angles
you should always start with the original problem
My assignment is that given two triangles that are Cogurrent, enumerate all the corresponding sides and angles
you can use whatever order you want for the first triangle
but for the name of the second triangle
the corresponding points will need to be in the same order
yes,
assuming they have been for some reason been represented with lowercase letters
But what about the sides? Seems tricky to do
sides between the corresponding angles would be corresponding
Anyone does have idea 🌚
(somewhat) famous problem https://www.cut-the-knot.org/triangle/80-80-20/IndexToLong.shtml
The length of the line segment
How is it used?
Wdym how it is used
AB means the length of the line segment joining A and B. Like i just said
So I can say AB = BC if seg AB is equal in length as BC?
Yes
What is the difference between AB and AB with a line over it?
Some people use AB with a line over it to emphasise that they’re talking about the line(/line segment) itself rather than its length
Some people don’t put a line over it for any occasion
You could say that
Oh
What does abc mean here?
You have a long way ahead of you then xd
Just learning triangle congruence
The angle ABC specifically means “the angle formed by the arms AB and BC”
Is <AB also valid?
No
Good to know
why ∆ACE = 10°
Oh I see 😁
is this a soild geometry channel ?
you can post solid geometry here
what is the vol of a parallelpiped if he gave me the 3 points in 3d directions ?
Guys I want to clarify something, if we have tan(nx) it's period is π/n right
I don't know how to put them into words
type in "period of tan nx"
help pls
Note that cos(pi/6 - x) = sin(pi/3 + x). That gives a pretty nice set-up for using a sum-to-product formula.
Do you mind telling me how you came up with this result please? I see that cos(pi/6-x)=sin(pi/3 - x/2) so I don't know where the mistake lies.
It just cos(a) = sin(pi/2 - a), and then simplify pi/2 - (pi/6- x) = pi/3 + x.
oh ok thank you very much
I need help with a test, I’m struggling
how did they get ybar = 215
for the triangle
you would think it would be 45/3 = 15, no?
Which triangle where?
i’m pretty sure this is really simple but i got it wrong:
a pyramid with a square base of a side length 8m has a height of 3m find the length of a sloping edge to once decimal place
show your attemp
you may find the value of the diagonal using Pythagorean theorem
where base^2 + height^2 = hypotenuse^2
since the diagonal cuts the rectangle into two congruent right triangles, then u can use the inverse of sin function (or the other trigo funcs) to find the angle (use calculator for convenience)
And refer to the theorems of parallel lines cut by a transversal so that you need not solve for the other right triangle's angle measures. Take note of the vertical angle theorem
for the first part, I would say that "also a blop" is like a bigger set that the set of "something is a blip" is enclosed in. Though, I am not completely sure.
For the second part, u may do the Pythagorean theorem i.e sec(theta)= a/n
is this correct?
contrapositive since normal = contrapositive (in truth values)
seems like it
after i subtract an area from another area, what is that red area called in english?
im a bit new to english math so i dont know those term
dunno of a special word for that. is there a term for it in your language?
remainder?
I don't know what to say
you can also say rectangular donut but I don't think that's a real word
Usually we just call it the shaded region
ah thats the word, thanks
imma die googling by myself to find that keyword
Hello! My question is about triangle congruency. SSS - side/side/side rule is that if all 3 sides of 2 triangles are equal, they are congruent. The reason for this is showed on the picture. We can see that triangles AB1C and AB2C are absolutely same, but how do we prove that?
Knowing that AB1 and AB2 are radii of the left circle, CB1 and CB2 are radii of the right circle, each pair of those sides have the exact same length. From there, as you said, it will be SSS congruency as they also share the side AC
hie
can anyone help me
to prove : if a triangle has two angles equal to one another than the sides subtending the equal angles will also be equal to one another.
can anyone??
But we are proving SSS! How can we prove SSS is true using SSS?
Ah I see... sorry for misunderstanding your question. I'd imagine it's something to do with the angles in the triangles, and the properties of isosceles triangles, since it's a super symmetrical figure, and the fact that it uses circles.
I will try to use it, thanks for the idea!
sin area
Multiply the two side lengths by the sin of 114 and divide the whole thing by 2
Let me rephrase that
$absin(c)/2$
Daniel S.
@river galleon A and B being your side lengths, and sin(114 degrees)
that was very helpful thank you
Is that a genuine expression or... Because it sounded sarcastic
not sarcasm
i do have a follow up question
what if you only have one side and two angles
for example 61 degrees 80 degrees and 17ft
to again find the area
Let me draw it out for you
Take this as an example
Are you asking, how to get 17 km
from your example how you got 60 and 54
Drawing a perpendicular line that bisects the two side lengths
But notice that I added 30 degrees as the angle
oh 30 60 90
Wait, I screwed up the triangle
XD
But, do you get the idea/
so when I find all the angles i can just use the same formula from before?
If the two side lengths are adjacent to the angle, then yes
✅
A ship sails on a bearing of 156°T until it is 45 km south of its starting point. How far
east is it, correct to two decimal places?
help
What does the T mean?
can someone dm I have somethings I need help with
You know sending the problem here works too
In fact you'll get more people to help you
Many helpers are motivated at least in part by the fact that they can be seen to be helpful and/or knowledgeable. If you want a closed DM conversation that motivation disappears.
Shhh don't expose us
lol
does anyone know how to solve or could point me in the right direction of finding the local min and max of 3/(4+2sinx-cosx) without differentiation?
harmonic trig identity
given a convex quadrilateral ABCD where ABC + ADC = 180°, is the quadrilateral always cyclic
im not sure if
cyclic quadrilateral -> ABC+ADC=180°
or
cyclic quadrilateral <-> ABC+ADC=180°
hm
well think of it this way
can you imagine a quadrilateral where opposite angles add up to 180 and it isn't cyclic
"The converse of this theorem is also true, which states that if opposite angles of a quadrilateral are supplementary, then the quadrilateral is cyclic."
I think this answers your question
supplementary angles are angles adding up to 180
yes thank you
np
could this be proven by dividing the quadrilateral into 4 right triangles
and then wait
let me try it
nvm
but thank you
I can’t find the answer anywhere on google so 😭
1.since ABC = ADC = 90, ABC+ADC=180 -> cyclic
2.since ABC=90, then AOC has to be 180 -> A, O, C are colinear -> diameter
this is correct right?
I just started learning about tangents and stuff and I’m confused how to solve for x here
Start with identifying what tan(49) would be in terms of the triangle parts
Remember that tangent is opposite/adjacent
Ok
Wait what is opposite/adjacent?
That would mean it would be tan(49)=14/x?
If I did it correctly I got x=16.1056
How do I solve for an angle using tangents when I have all the sides and a 90 degree angle alr?
Like this
Could anyone dm me a good trigonometry book recommendations? 😄
Pythagorean theorem to find the height
Then you base times height your way to victory
Use your knowledge of angles and trig functions to solve this problem
bro i dont have knowledge of everything i literally flunked school
ok find dis angle using trig and then u can find the base of that triangle on the left with more trig functions and then do the same with the other triangle and then use base times height divided by 2
then just add all of it up
send the full question ty
Hi, can I get a help or tips about these problems?
What is the area of quadrilateral ABCD given 2 sides and radius of inscribed circle? AD= 5cm, BC = 4cm, radius of circle is 2 cm
And how to find the length of a radius of circumscribed circle around a regular hexagon, if I know the length of the radius of inscribed in it circle (it is 6√3 cm)?
also has something to do with special triangle 45-45-90 caSE
for geo, always make a diagram
art of problem solving precalculus
Set up your equation as normal with SOHCAHTOA, but this time, theta is your unknown variable. You'll have to solve for theta using an inverse tangent
What do you think this is? Google, Chat gpt, Twitter?
@timber cargo Bro be fr
we're here to guide you on getting it.
Could someone point out my error here? The answer should be 0 if you use the 1+tan^2(5) identity. But shouldn't this work too? I'm sure it's a stupid mistake, but I'm not seeing it.
This should be a negative sign
Why?
b/c $\sin^2 5^{\circ}-1=-(1-\sin^2 5^{\circ})=-\cos^2 5^{\circ}$
Cos square theta plus sine square theta is one
Civil Service Pigeon
🤣 I knew it was something stupid. Thank you!
Angle C and E are flipped
Determine all values of k for which the points A=(1,2), B=(11,12), and C=(k,6) form the vertices of a right-angled triangle.
I tried this using the pythagorean theorem by calculating AB^2, AC^2, and BC^2 and using the Pythagorean theorem but i'm not getting the right answer
maybe you could show us your working
AB^2 = (11-1)^2 + (12-2)^2 = 200
AC^2 = (k-1)^2 + (6-2)^2 = k^2-2k+17
BC^2 = (k-11)^2 + (6-12)^2 = k^2 - 22k + 157
Isn’t it all the points on a circle
after that what did you do
AB^2 + AC^2 = BC^2
simplifying this you get k = -3
if you sub in the values
the answer is supposed to be 1 and 11 i believe
...hey, where did the 12 come from?
it's supposed to be 2 i think
I NEED HELPPP
This is every point for a right triangle using those 2 points
I think
is that the answer given? because i think there should be 4 answers
Ion know y this is wrong... what's my mistake?
yeah it only says 1 and 11
how do you get that?
for k = 3 and 9 <ACB is 90 deg
for k = 1 <CAB is 90 deg
for k = 11 <ABC is 90 deg
but how did you find those numbers?
could you explain it? im not really sure
isnt AB on an angle?
?
if its going from (1,2) to (11,12)
oh yes sorry i wrote the wrong number
is that true or is your original message true because you made a typo
i meant 11,12
sorry, my mistake
?
sorry its 1 and 13 thats the answer 😭
i screwed up the numbers
Determine all values of k for which the points A=(1,2), B=(11,12), and C=(k,6) form the vertices of a right-angled triangle.
the answer is 1 and 13
huh i got -1, 13 and others
Knowing that $C = 2\pi r \implies r = \frac C{2\pi}$, we can say that:
$$\begin{align*}
A &= \pi r^2 \
&= \pi\parens{\frac C{2\pi}}^2 \
&= \frac{C^2}{4\pi}
\end{align*}$$
You can plug in $C$ directly. It's probably an intermediate rounding error that caused you to goof up because your work is fine.
Umbraleviathan
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
Yup
Although it only wants points on the circle where y = 6
Which has two answers
Either you use projection or pythag
Although your circle uses (11,2) instead of (11,12)
Please help. (This is probably a easy geometry question, but I don't know how to do it)
The two triangles are similar, meaning their side lengths are in proportion
24 is proportional to 8 as 10 is to x
so
24-8
10-x
solve for x by cross multiplying
or you can just do this intuitively
and see that it’s 10/3
^ This should help you with analyzing future problems
But do you understand why
I think that if the shape of both of the triangles is similar, it is proportional.
the bigger one was essentially just scaled up to a factor of 3
Thanks
can someone help me with my problem (help -12)
I got 436.9
You probably shouldn't have rounded the value of r at the start
Just kept it as it is, square it and multiply with pie
C^2/4pi^2
don't forget
It's 436.944776539
You rounded your r, don't do that
do vectors belong here or somehwere else
#linear-algebra probably
can someone please explain this to me
because 36.8*2
and 180- the sum = 106
which is wrong
and hwo they got the equation at the bottom
complete ss
or how do they prove tan^2 x = 0.5
I dont' understand that part
why does a conic section always touch the cone in one point?
<@&268886789983436800>
Aww what did I miss
porn
Ah yes
very weird porn
what are tangent circles
circles that touch each other at exactly one point
Set (3x+19) equal to (4x+14)
Solve for x
y+(3x+19) are supplementary
they add up to 180 degrees
If you know what x is, you’ll know what y is
If x is 5, what is then 3x+19?
Yes, but does 34 + 24 make 180?
no
Is anyone good with factors ?
So x=5, y=24 is not a solution.
can someone help me with this please
could someone teach me how to identify the side lengths
i'm not sure why it's so difficult for me
i feel like it should be easy
Find RQ and Triangle of PRQ
me and my whole class has trouble with this 😂
ifa nyone wanna help
u shouyld extand the line PQ
and create a perpeniducular from R to that line
then u can use the cosine
to identity the whole adjacent line
Since it's an SAS case, u may refer to law of cosine where p^2 (or segment RQ^2) = q^2 + r^2 - 2qr cos(45deg)
yea i think so as well
my plesesure
have u got what u have to do
?
U can use cosine to get the value of PQ'
then u can get QQ' and same way u can get the valuye of RQ' using sine
u mean 10cos45deg correct?
or im confused, lol
oh wait
SO from here u can get the value of PQ'
I essentially just got the value of PQ'
Okay good
since it's a right triangle, i just did 10cos45deg.. is this correct?
for triangle PRQ'
45
45*
Oh then u can just use cos 45
