Introduction to rotation
A transformation in which a plane figure turns around a fixed center point called center of rotation. A rotation in the anticlockwise direction is taken to be positive whereas a rotation in the clockwise direction is taken to be negative.For example a rotation of #90^0# clockwise is taken to be negative. #- 90^0# while a rotation of anticlockwise #90^0# is taken to be #+90^0#. For a rotation to be completely defined the center and the angle of rotation must be stated.