Mathematics for IGCSE & O level - Symmetry (Section 1 - No. 39)
What can we conclude if a shape has no rotational symmetry?
It has no lines of symmetry.
It will look identical only once in a complete turn.
It does not reflect onto itself in a line.
It has rotational symmetry of order 1.
解释
If it has no rotational symmetry, the only time a shape with fit itself in one rotation is at the start and end.