question_answer

Give the order of rotational symmetry for each figure:

(a)

(b)

(c)

Answer:

Let us mark a point A on each figure and also indicated the angle through which the figure is to be rotated as under:

(a)

(b)

(c)

Now to find the rotational symmetry, we proceed as under:

In figure (a): It requires two rotations, each through an angle of 180°, about the marked point (×) to come back to its original position. So, its rotational symmetry is of order 2.

In figure (b): It requires four rotations, each through an angle of 90°, about the marked point (×) to come back to its original position. So, its rotational symmetry is of order 4.

In figure (c): It requires three rotations, each through an angle of 120°, about the marked point (×) to come back to its original position. So, its rotational symmetry is of order 3.