Question

The radius of a circle is 12 miles. What is the angle measure of an arc bounding a sector with area 10​ square miles?

Answer 1

$\bf \textit{area of a sector of a circle}\\\\ A=\cfrac{\theta \pi r^2}{360}~~ \begin{cases} r=radius\\ \theta =angle~in\\ \qquad degrees\\[-0.5em] \hrulefill\\ A=10\\ r=12 \end{cases}\implies 10=\cfrac{\theta \pi 12^2}{360}\implies 10=\cfrac{2\pi \theta }{5} \\\\\\ 20=2\pi \theta \implies \cfrac{20}{2\pi }=\theta \implies \cfrac{10}{\pi }=\theta \implies 3.18\approx \theta$