Radian

The radian (symbol rad) is the unit for measuring angles, and is the standard unit of angular measure used in many areas of mathematics.

The length of an arc of a unit circle is numerically equal to the measurement in radians of the angle that it subtends. An arc of a circle with the same length as the radius of that circle subtends an angle of 1 radian. The circumference subtends an angle of 2π radians.

Conversions

Radians	Degrees
0	0°
π/12	15°
π/6	30°
π/4	45°
1	57.3°
π/3	60°
π/2	90°
π	180°
2π	360°

References

• Wikipedia