Question

find the measure of the angle of the radius of the circle is 4 inches and the length of the arc is 8 pi.

Answer 1

Since the angle is in radians, then s = rθ.

$\bf \textit{arc's length}\\\\ s=r\theta \quad \begin{cases} r=4\\ s=8\pi \end{cases}\implies 8\pi =4\theta \implies \cfrac{8\pi }{4}=\theta \implies 2\pi =\theta$