It makes us think there is new information or a follow-up question and we spend time opening the thread. Simply click on the Thank button at the bottom left-hand corner of any post you find helpful. I agree with Mike.
Symmetry comes from a Greek word meaning 'to measure together' and is widely used in the study of geometry. Mathematically, symmetry means that one shape becomes exactly like another when you move it in some way: turn, flip or slide.
Symmetry means measures the same.. So, starting at one point on one of the faces, how far do you have to rotate to reach the point that measures the same or looks the same again? The same place on the next face, right? So how far is that?