Question

What is the area of a shaded sector if the diameter is 20

Answer 1

So.. hmm notice the picture below... if the diameter is 20, the radius is half that

thus $\bf \textit{area of a circle's sector}\\\\ A=\cfrac{\theta\pi r^2}{360}\qquad \begin{cases} r=radius\\ \theta=\textit{angle in degrees} \end{cases}$