What is the smallest angle of rotational symmetry that maps a regular pentagon onto itself? enter your answer in the box.

Consider the regular pentagon ABCDE, with center (of mass)  O.

The central angle O is a complete angle, so its measure is 360°.

It is divided into 5 equal parts, so each of them has a measure of 360°/5=72°.

If we rotate the pentagon, with point O as the center of the rotation, we can map A to any of the other points.

The smallest angle of rotation is the angle which mas A to E, 72°.

72°

In the first triangle 80+20+p=180 (since sum of all angles of a triangle is 180)so p= 80also in second triangle 55+45+q=180 (since sum of all angles of a triangle is 180)so q=80so we can conclude that p=80 degrees q=80 degrees so p=q=80 degreeshence option b is correct