OpenSAT

The area of a circle is given by $A = \pi r^2$, where $r$ is the radius of the circle. We are given that the area is $16\pi$ square inches, so $16\pi = \pi r^2$. Dividing both sides by $\pi$ gives $16 = r^2$, so $r = 4$. The circumference of a circle is given by $C = 2\pi r$, so $C = 2\pi (4) = 8\pi$.