## Functions Modeling Change: A Preparation for Calculus, 5th Edition

$\frac{\pi^2}{30}$ rad.
Using the fact that $\pi \: \textrm{rad.} = 180^\circ$, $$6\pi^\circ \cdot \frac{\pi \: \textrm{rad.}}{180^\circ}=\frac{\pi^2}{30}$$