Rotation

Definition:  Given a fixed point O, called the center of rotation, rotation about the center is a transformation that maps every point P to a point P' such that the following properties are satisfied:  

  1. PO = P'O 
  2. The angle POP' is congruent to the angle of rotation.

Example:

 The point P' is the rotation of point P through the given angle of 60 degrees.