UNITS A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site radian One of two supplementary (dimensionless) units in the SI system of units (the other being the steradian). The radian is a unit of plane angle. There are 2π radians in a complete circle. One radian = 180/π degrees, or approximately 57.296°. Related category    • UNITS Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP