[tex]\bf \textit{area of a sector of a circle}\\\\
A=\cfrac{\theta \pi r^2}{360}\quad
\begin{cases}
r=radius\\
\theta =angle~in\\
\qquad degrees\\
------\\
r=9\\
\theta =50
\end{cases}\implies A=\cfrac{50\cdot \pi \cdot 9^2}{360}\implies A=\cfrac{45\pi }{4}[/tex]
