The angle of rotation by which the image of a regular pentagon coincide with its pre-image is:
72°
Regular polygon--
A regular polygon is a polygon in which all the sides and all the interior angles are equal i.e. the polygon is equilateral and equiangular.
In general the angle of rotation of a regular n-polygon is given by:
[tex]\dfrac{360}{n}[/tex]
where n is the number of sides in a polygon.
Here we have n=5 (pentagon)
Hence, the angle of rotation of the image is:
[tex]\dfrac{360}{5}=72[/tex]