Question

Find the number of sides in a polygon if the sum of its interior angle is: 1620°

Answer 1

Let no. of sides = n

∴ Sum of angles of polygon = 1620°

∴ (2n - a) × 90° = 1620°

⇒ 2(n - 2) = `(1620°)/(90°)`

⇒ n - 2 = `(1620°)/(2 xx 90°)`

⇒ n - 2 = 9

⇒ n = 9 + 2

⇒ n = 11