http://i56.tinypic.com/r1esm0.png
Find the radius, the perimeter(solid blue) is 25.
I'm TA for my old math teacher, and he asked me to find out the answer to this for his honors geometrey class, just for old times sake(we always used to do these little challenges), and this time i'm stumped. He also doesn't know how to do this, so he has me, and every other math teacher working on this. I figured you guys are smarter :)

