Question

Which of the following cannot be the angle of rotational symmetry of a regular polygon?

• A. ${40}^{\circ }$
• B. ${72}^{\circ }$
• C. ${180}^{\circ }$
• D. ${120}^{\circ }$

Answer 1

The correct option is C

${180}^{\circ }$

The angle of rotation of a 'n' sided regular polygon is given by $\frac{{360}^{\circ }}{n}.$

We know that minimum value of $n$ is 3 as the minimum number of sides required to make a polygon is 3.
Also, $\frac{{360}^{\circ }}{3}={120}^{\circ }.$
$\therefore$ The angle of rotational symmetry of a regular polygon will always be less than or equal to ${120}^{\circ }.$