Standard

A radian is a unit of measuring angles just like a degree is. A radian is a distance on the circle’s circumference which is equal to 1 radius.

This means there are $2\pi$ radians in one circle or that $2\pi$ radians equals 360 degrees.

If $2\pi$ radians equals 360 degrees that means that 1 degree equals $2\pi$ divided by 360 radians or $\pi$ divided by 180 radians.

1 radian = $\frac{180}{\pi}$ degrees

1 degree = $\frac{\pi}{180}$ radians

This is a degrees and radians chart. If 1 degree = $\frac{\pi}{180}$radians then 30 degrees equals 30 times that or $\frac{\pi}{6}$ radians. The same thing can be done to find the radian measure for other angles.