OpenSAT

The circumference of a circle is given by the formula $C = 2\pi r$, where $r$ is the radius of the circle. We are given that $C = 12\pi$, so we can solve for the radius: \begin{align*} 12\pi &= 2\pi r \\ \Rightarrow \qquad 6 &= r \end{align*} The area of a circle is given by the formula $A = \pi r^2$. Substituting 6 for $r$ gives us $A = \pi (6)^2 = 36\pi$.