Question

The regular pentagon ABCDE rotates counterclockwise about its center to form pentagon A′B′C′D′E′. The angle of rotation at which point A′ coincides with point D is ___°.

Answer 1

now, let's consider what happens when you rotate counterclockwise to the next set of points



this represents a (360/5) = 72 degree rotation. now, consider how many of such rotations you would need to get D to A'.