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Mathematics 10 Online
OpenStudy (anonymous):

Can someone explain how this is the answer to this question. (picture attached)

OpenStudy (anonymous):

uhh...i can try

OpenStudy (anonymous):

OpenStudy (anonymous):

that is the question, i messed up on the notes and got confused lol

OpenStudy (anonymous):

lol uhh..im kinda confused too but i love your hand writing :)

OpenStudy (anonymous):

@helpme1.2 can you help us

OpenStudy (anonymous):

@heybhai can you help too if you dont mind

OpenStudy (anonymous):

Give me 3 mins @GamerGirl.1

OpenStudy (anonymous):

@iPwnBunnies can you help all of these people are smart :) they can help us

OpenStudy (anonymous):

ok

OpenStudy (anonymous):

haha thank you :)

OpenStudy (anonymous):

your welcome

OpenStudy (ipwnbunnies):

Oh man, this might get confusing trying to explain it in typing.

OpenStudy (anonymous):

it's all right as long as u label stuff like "step 1, step 2" etc

OpenStudy (ipwnbunnies):

It looks like you have a good hold on math due to the stuff around the problem, I'll see if I can just write it in words.

OpenStudy (anonymous):

its ok

OpenStudy (ipwnbunnies):

Welp, the area of the circle is pi*r^2, we can start from there. A side of the triangle is the same length as the radius.

OpenStudy (anonymous):

i feel like im in math class...

OpenStudy (anonymous):

oh yeah it was an equilateral triangle

OpenStudy (ipwnbunnies):

Ooo, do you know something I don't know? The area of a sector of the circle, what is that?

OpenStudy (ipwnbunnies):

Don't tell me, hold on.

OpenStudy (ipwnbunnies):

Do you agree that the area of segment = area of sector - area of triangle?

OpenStudy (anonymous):

hmm

OpenStudy (anonymous):

i do agree

OpenStudy (ipwnbunnies):

Good, so. The shaded region = area of the circle - area of the segment?

OpenStudy (anonymous):

yes

OpenStudy (ipwnbunnies):

Great. Therefore, shaded region = area circle - (area of sector - area of triangle)

OpenStudy (ipwnbunnies):

The thing is that I don't think I don't know theformula for the sector of a circle. I remember arclength = radius*angle(radians)

OpenStudy (anonymous):

ooooh i know how to find the sector, it's the triangle I'm confused about

OpenStudy (anonymous):

the sector formula is arc degree/360 * pi(r^2)

OpenStudy (anonymous):

i think

OpenStudy (ipwnbunnies):

Break it up into two right triangles. Find the area of one of them and multiply by two.

OpenStudy (ipwnbunnies):

This is like the ultimate Precalc problem.

OpenStudy (anonymous):

so it should look like 60/360 x pi12^2 and, wouldn't that make the triangle a 30-60-90 triangle?

OpenStudy (anonymous):

ahahah thats funny I'm only in regular geo

OpenStudy (ipwnbunnies):

Yeah, the right triangle you created would be a 30-60-90 triangle. And I won't know the answer b/c I don't know the area of a sector lol.

OpenStudy (anonymous):

hah @iPwnBunnies your smart :)

OpenStudy (anonymous):

oh snap i think i got it actually

OpenStudy (anonymous):

i was just watching.. and writing ...

OpenStudy (ipwnbunnies):

Make sure you're using radians for theta, if you're using this formula for Area of a sector: A(sector) = (1/2)*theta*r^2

OpenStudy (anonymous):

i never learned theta yet, i was using a dif formula

OpenStudy (ipwnbunnies):

Oh, sorry. Theta means the angle.

OpenStudy (anonymous):

ooooh well the sector is 24pi

OpenStudy (anonymous):

but now idk what comes after that

OpenStudy (ipwnbunnies):

Alright, I'm just saying you might get the wrong answer if you're using the wrong units. Idk the formula you have.

OpenStudy (ipwnbunnies):

Did you find the area of the "right triangle" yet? I'll write out what we found so far. Shaded region = area of circle - (area of sector - area of triangle)

OpenStudy (anonymous):

no, i couldn't figure the triangle out

OpenStudy (ipwnbunnies):

Shaded region = 144pi - 24pi - area of triangle

OpenStudy (ipwnbunnies):

Alright, hold on.

OpenStudy (anonymous):

oh wait is the area 36 (square root) 3

OpenStudy (ipwnbunnies):

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