The radian is the standard unit of angular measure, used in many areas of mathematics. It describes the plane angle subtended by a circular arc as the length of the arc divided by the radius of the arc. The unit was formerly a SI supplementary unit, but this category was abolished in 1995 and the radian is now considered a SI derived unit. The SI unit of solid angle measurement is the steradian.
Conversion between radians and degrees
A chart to convert between degrees and radians
As stated, one radian is equal to 180/π degrees. Thus, to convert from radians to degrees, multiply by 180/π.
Conversely, to convert from degrees to radians, multiply by π/180.