Question

If a fan has 3 blades, then its degree of rotation is _____.

• A. ${90}^{\circ }$
• B. ${120}^{\circ }$
• C. ${150}^{\circ }$
• D. ${180}^{\circ }$

Answer 1

The correct option is B

${120}^{\circ }$

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 ${120}^{\circ }.$