Rotational Symmetry

Drag the slider from left to right to rotate the polygons. The position of the slider indicates the specific angle of rotation.
If the polygon is mapped to itself after a rotation of between 0 and 360 degrees, the shape has rotational symmetry. Which of these shapes have rotational symmetry? Which do not? For the shapes that have rotational symmetry, for what angle measure(s) does the figure map to itself?