ROTATIONAL SYMMETRY

A shape has Rotational Symmetry when it still looks the same after some rotation (of less than one full turn).        

EXAMPLE 2.

What is the order of rotational symmetry of a regular pentagon

Solution

If a regular pentagon is rotated by 72° (one fifth of 360°), then it exactly fits its own outline.
Therefore a regular pentagon has rotational symmetry of order 5.