[tex]\bf \textit{area of a circle}\\\\
A=\pi r^2\qquad A=49\implies 49=\pi r^2
\\\\\\
\sqrt{\cfrac{49}{\pi }}=r\implies \cfrac{7}{\sqrt{\pi }}=\boxed{r}\\\\
-----------------------------\\\\
\textit{circumference of a circle}\\\\
C=2\pi r\implies C=2\pi \left( \boxed{\cfrac{7}{\sqrt{\pi }}} \right)[/tex]
simplify, if you need to
