Math Help - Three quarter circle problem...

1. Three quarter circle problem...

My first post! I do have a question about three quarters of a circle perimeter question. It said the perimeter is 572. How do you separate the straight edges? What is the solution? Thanks for all your help!

2. Re: Three quarter circle problem...

Originally Posted by evilgummybear
My first post! I do have a question about three quarters of a circle perimeter question. It said the perimeter is 572. How do you separate the straight edges? What is the solution? Thanks for all your help!
1. Draw a sketch (or use a pizza and eat one quarter of it )

2. The perimeter of three quarters of a circle consists of 2 radii and the corresponding arc which is 3/4 of the perimeter of a circle.
Thus you have:

$2r + \frac34 \cdot 2\pi \cdot r = 572$

Solve for r.

3. You should come out with $r \approx 85.22$