Answer-
When rotated a angle of 72°, a regular pentagon coincides with its pre-image.
Solution-
A polygon is regular when all angles are equal and all sides are equal. So, when a pentagon's all 5 angles and sides are equal then it's called as a regular pentagon.
The angel subtended by two consecutive radius of a regular pentagon(i.e the line joining vertices and the center of the pentagon) at the center is 72°.
Due to its symmetry when a regular pentagon is rotated 72° around its center(both clockwise and counter-clockwise), it produces same pentagon as before.
