CTET 2 Math and Science 7 Jan 2022 Paper

Let n be the number of sides
⇒ ( 2n - 4 ) × 90 = 1080°
⇒ 2n - 4 = 1080 / 90
⇒ 2n - 4 = 12
⇒ 2n = 12 + 4 = 16
⇒ Each angle = 1080 / 8 = 135
⇒ 180 - 135 = 45 each exterior angle
⇒ Exterior angle = 45°
∴ The measure of its each exterior angle 45°.