Question

Please help me!

Answer 1

$\bf \textit{area of a sector of a circle}\\\\ A=\cfrac{\theta r^2}{2}~~ \begin{cases} r=radius\\ \theta =angle~in\\ \qquad radians\\ ------\\ r=5\\ \theta =\frac{\pi }{4} \end{cases}\implies A=\cfrac{\frac{\pi }{4}\cdot 5^2}{2}\implies A=\cfrac{\quad \frac{25\pi }{4}\quad }{\frac{2}{1}} \\\\\\ A=\cfrac{25\pi }{4}\cdot \cfrac{1}{2}\implies A=\cfrac{25\pi }{8}$