Answer
$\frac{\pi}{3}$
Work Step by Step
$\cos s=\frac{1}{2}$ can be rearranged as $s=\cos^{-1} (\frac{1}{2})$.
Ensuring that the calculator is in radians, we type $\cos^{-1} (\frac{1}{2})$ into the calculator and solve.
Therefore,
$s=\cos^{-1} (\frac{1}{2})=\frac{\pi}{3}$
