A regular hexagon has rotational symmetry and can be rotated by certain angles that will map it onto itself. The angles of rotation that result in the hexagon looking the same are multiples of
(1/6 of a full rotation) (2/6 of a full rotation) (3/6 of a full rotation) (4/6 of a full rotation) (5/6 of a full rotation) (full rotation)
Excluding