Question

Find the number of side of a polygon, if the sum of its interior angle is: 1440°

Answer 1

1440°

Let no. of. sides = n

∴ Sum of interior angles of polygon = 1440°

∴ (2n - 4) × 90° = 1440°

⇒ 2n - 4 = `(1440°)/(90°)`

⇒ 2(n - 2) = `(1440°)/(90°)`

⇒ n - 2 = `(1440°)/(2 xx 90°)`

⇒ n - 2 = 8

⇒ n = 8 + 2

⇒ n = 10