Students will learn how to find the order of rotational symmetry for various shapes. They'll do this by marking a point on the given shape, then counting the number of rotations for which the figure looks the same. For example, an equilateral triangle has order 3 rotational symmetry, because if we mark an equilateral triangle at its apex, there are three rotations for which it looks the same. The first, is to not rotate the triangle at all. The second, is to rotate it 1/3 of the way around. The third, is to rotate it 2/3 of the way around. We could of course, rotate the figure all the way around, but that would be the same as not rotating it at all.
Conclude by leading this investigation: