Question

Find the order of rotational symmetry for a fan if it has three blades.

• A. 3

Answer 1

The correct option is A 3
Since the fan has three blades, the central angle is divided into 3 equal parts. This gives $\frac{{360}^{\circ }}{3}={120}^{\circ }.$
Angle of rotation is the smallest angle for which the figure can be rotated to coincide with itself.
So, the degree of rotation of the fan is ${120}^{\circ }.$
$\therefore$ Order of rotational symmetry $=\frac{{360}^{\circ }}{\text{minimum angle of rotation}}=\frac{{360}^{\circ }}{{120}^{\circ }}=3$