An octagon has eight sides of equal length and eight angles of same measure. So, If it is rotated 360 degrees about its center. It would coincide with all of its 8 sides. So, it will coincide with it's pre-image 8 times.
because A regular octagon is a closed figure with sides of the same length and internal angles of the same size. so if it is rotated 360 degrees it should coincide with its preimage after every 45 degrees.
