Degrees to Radians

$\pi$ radians and 180° are the same half turn. Divide both by 180: one degree is $\frac{\pi}{180}$ radians. So multiply an angle in degrees by $\frac{\pi}{180}$ to get radians.

Take 150°: $\frac{150\cdot \pi}{180}$. 150 and 180 share a factor of 30, so the fraction reduces to 5/6 and 150° is $\frac{5\pi}{6}$ radians.

Leave radian answers as a fraction of $\pi$. That keeps them exact and shows the size at a glance: $\frac{5\pi}{6}$ is five sixths of a half turn, just short of $\pi$.