Definitions. I don't know if I wrote them in english correctly. The usual units of measurement for angles are degrees, denoted by ° and radians, denoted by rad or without any unit. One full rotation is 360° and 2π rad. To turn degrees into radiants and vice versa, it is used this proportion -> 180 : gr = π : rad "gr" is the measurement in degrees of the angle, "rad" is the measurement in rads of the same angle. 1 rad = 180°/π = 57,29578° = 57° 17’ 45” Example. Turn 135° in rads: 180 :135 : = π : rad -------> rad = 135 π/180 --------> rad = 3 π/4 ----------> rad = 3/4 π