Question

Find the measure of each interior angle of a regular polygon of $9$ sides.

• A. ${160}^{\circ }$
• B. ${180}^{\circ }$
• C. ${120}^{\circ }$
• D. ${140}^{\circ }$

Answer 1

The correct option is D ${140}^{\circ }$

Each interior angle of regular polygon of $n$ sides is given by $\frac{180(n-2)}{n}$ degree
$\therefore$ each interior angle $=\frac{180(9-2)}{9}$ degree
$=20\times 7$

$={140}^0$