Question

The circumfrence is 16 pi. What is the are in terms of pi?

Answer 1

$\bf \textit{circumference of a circle}\\\\ C=2\pi r~ \begin{cases} r=radius\\ -----\\ C=16\pi \end{cases}\implies 16\pi =2\pi r\implies \cfrac{16\pi }{2\pi }=r\implies \boxed{8=r}\\\\ -------------------------------\\\\ \textit{area of a circle}\\\\ A=\pi r^2\qquad \qquad \qquad \implies A=\pi (8)^2\implies A=64\pi$