Suppose the measures of four angles are 3x, 5x, 9x and 13x.
∴ 3x + 5x + 9x + 13x = 360° [Angle sum property of a quadrilateral]
⇒ 30x = 360°
⇒ x = 360/ 30 ° = 12°
⇒ 3x = 3 × 12° = 36°
5x = 5 × 12° = 60°
9x = 9 × 12° = 108°
13x = 13 × 12° = 156°
∴ the angles of the quadrilateral are 36°, 60°, 108° and 156° Ans
