Question

What is the area with circumference 36pi cm

Answer 1

$\bf \textit{circumference of a circle}\\\\ C=2\pi r\qquad \begin{cases} r=radius\\ -----\\ C=36\pi \end{cases}\implies 36\pi =2\pi r \\\\\\ \cfrac{36\pi }{2\pi }=r\implies \boxed{18=r}\\\\ -------------------------------\\\\ \textit{area of a circle}\\\\ A=\pi r^2\qquad A=\pi \cdot \boxed{18}^2$