In Exercises $77-80$ , find the radian measure of the central angle of a circle of radius $r$ that intercepts an are of length $s$ .
$$
\begin{array}{cc}{\text {Radius } r} & {\text {Arc} \text {Length } s} \\ {14.5 \text { centimeters}} & {35 \text { centimeters }}\end{array}
$$