Angle measure

A full rotation measures $360^{\circ }$ or $2\pi$ radians. To convert degrees to radians, multiply by $\frac{\pi }{180}$. To convert radians to degrees, multiply by $\frac{180}{\pi }$. The arc length $s$ traveled along a circle of radius $r$ through an angle $\theta$ measured in radians is $s=r\theta$. If an object completes $n$ revolutions per minute, its linear speed is $n$ times the circumference of its circular path per minute.