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Mathematics 19 Online
OpenStudy (anonymous):

will someone please go to this website i need help with problems 8-12 please http://docs.google.com/viewer?a=v&q=cache:s_Z6mEDtqnAJ:www.somersclassroom.com/files/Chapter%252011/11.5B.pdf+Answers+to+Practice+B+11.5+Geometry&hl=en&gl=us&pid=bl&srcid=ADGEEShpElU6i2Z7y85NrrTvbtv6Xn4WJVYyv7dLeO0itxvLzove7oq8uuVBixJhT8WeHarT3fU7H8VLiD-lB3r80ml3tteJXW5mtG0dWFZFEwSrLDZiHxlXHME_wCAUoHME2QVUFMpY&sig=AHIEtbRN3mHn7LH_nAJkKRNhqf_6RQ8gLw

OpenStudy (anonymous):

not getting through with the link

OpenStudy (anonymous):

the link works you just need to copy and paste the whole link, not just what is underlined

OpenStudy (anonymous):

can someone help me with 8-12?

OpenStudy (anonymous):

could you be more specific with what you are finding difficult about, for instance # 8?

OpenStudy (anonymous):

i just dont know how to do them

OpenStudy (anonymous):

like if i can just get the equation i can find the answers.. i just need the equation

OpenStudy (anonymous):

well in # 8 the tringle is an equilateral triangle, so you know all the angles already. Since you are given the radius of the circle, you can use the equation A=pi*r^2

OpenStudy (anonymous):

to find the area of the circle and then subtract the area of the triangle from the area of the circle.

OpenStudy (anonymous):

the sides of the triangle are all 6 btw

OpenStudy (anonymous):

so the area of the triangle is 15.59

OpenStudy (anonymous):

so the circle area would be about 34.65?

OpenStudy (anonymous):

one sec

OpenStudy (anonymous):

first cut the triangle in half to make two right angle triangles. then you can use pythagorean to find the height of the triangle, which i got to be sqrt(27). finding the area of the triangle with half base times height formula, 1/2*6*sqrt(27) = 9sqrt(3) =15.59. Is that what you did?

OpenStudy (anonymous):

yea

OpenStudy (anonymous):

for the area of the circle did you use pi*r^2?

OpenStudy (anonymous):

yeah and i got 50.24

OpenStudy (anonymous):

plugging in 16 for r^2, i got the area to be 50.27

OpenStudy (anonymous):

so subtract the area of the triangle from the area of the circle to find the area of the shaded region

OpenStudy (anonymous):

34.68

OpenStudy (anonymous):

super

OpenStudy (anonymous):

would it be squared?

OpenStudy (anonymous):

no, why would you?

OpenStudy (anonymous):

idk.. someone helped me with number 7 and they squared it

OpenStudy (anonymous):

might have been part of finding the area of a circle, you need to square the radius for that

OpenStudy (anonymous):

we already did that, though, so it's fine as it is

OpenStudy (anonymous):

okay.. will you help me with the other ones

OpenStudy (anonymous):

well, I have a bit of hw of my own that i must do before tomorrow, but take a look at number 12... I want to try doing that one with you.

OpenStudy (anonymous):

if you like

OpenStudy (anonymous):

ok

OpenStudy (anonymous):

This is a really cool and beautiful one out of the lot. do you see any way of starting to think about it?

OpenStudy (anonymous):

doing A=pi*r^2

OpenStudy (anonymous):

that would give you the area of the circle, it's true. but look even more closely: there are only two lines in the triangle that you do not know the length of... right?

OpenStudy (anonymous):

yea

OpenStudy (anonymous):

oops... I meant to say in the circle

OpenStudy (anonymous):

and do you know the equation to find a sector a circle?

OpenStudy (anonymous):

arc divided by 360* pi*r^2

OpenStudy (anonymous):

A=1/2*r^2*theta

OpenStudy (anonymous):

actually since each of these sectors is 1/4 of the circle, the equation is A=1/4*pi*r^2

OpenStudy (anonymous):

do you see where I'm going with this?

OpenStudy (anonymous):

so a=1/4*3.14*6^2

OpenStudy (anonymous):

=28.26

OpenStudy (anonymous):

well the area of the triangle is 18 right?

OpenStudy (anonymous):

yea

OpenStudy (anonymous):

good, and so given that you now have the area of a quarter of a circle, and the area of the triangle, you can subtract the area of the triangle away from the area of the quarter of the circle that you have.

OpenStudy (anonymous):

sorry i skipped a step before. have you followed me up to this point or are you a bit lost?

OpenStudy (anonymous):

So, here are the steps. 1) we found the area of a quarter of a circle. 2) we found the area of the triangle. 3) we subtract the area of the triangle from the area of the quarter of the circle in order to find the area of one of the shaded regions.

OpenStudy (anonymous):

but since both of the triangles are the same, we also now know the area of the other shaded region. does that make sense?

OpenStudy (anonymous):

yea

OpenStudy (anonymous):

Awesome. I'm glad I could help :) This is my first time on this site, but this is a pretty cool idea for a site.

OpenStudy (anonymous):

yeah

OpenStudy (anonymous):

well I have to go do HW now, good luck!

OpenStudy (anonymous):

thank you for your help

OpenStudy (anonymous):

no problem

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