Question

A circle has a radius of

Answer 1

$\bf s=r\theta\qquad \begin{cases} s=\textit{arc's length}\\ r=radius\\ \theta=\textit{central angle in radians}\\ \qquad \textit{made/subtended by the angle }\theta \end{cases}\implies \cfrac{s}{r}=\theta$

you're given both, plug them in