Find the exact circumference of a circle with an area equal to 36pi sq. in.

a. 12pi

b. 18pi

c. 324pi

12 pi. So the equation for area is pi (r) squared so you have to set pi (r) squared equal to 36 and solve for "r". R is equal to six. After, you use "r" in the circumference formula which is 2 (pi) r which would be 2 (pi) 6 which equals to 12pi