The radian, in mathematics, is a unit of plane angle, equal to 180/? degrees, or about 57.2958 degrees. It is represented by the symbol "rad" or, more rarely, by the superscript c (for "circular measure"). For example, an angle of 1.2 radians would be written as "1.2 rad" or "1.2c" (the second symbol can be mistaken for a degree: "1.2°").However, the radian is the standard unit of angular measurement for mathematicians, and in mathematical writing the symbol "rad" is almost always omitted. In th