[tex]\bf \textit{circumference of a circle}\\\\
C=2\pi r\quad
\begin{cases}
r=radius\\
-----\\
C=125.6
\end{cases}\implies 125.6=2\pi r\implies \cfrac{125.6}{2\pi }=\boxed{r}
\\\\\\
\textit{area of a circle}\\\\
A=\pi r^2\qquad \qquad \implies A=\pi \left( \boxed{\cfrac{125.6}{2\pi} } \right)^2[/tex]
