Given: Ratio of the angles of a triangle = 2 : 4 : 3 Formula: Sum of angles of a triangle 180° Calculation: Ratio of angles of a triangle = 2x : 4x : 3x According to the question 2x + 4x + 3x = 180° ⇒ 9x = 180° ⇒ x = 180°/9 ⇒ x = 20° Smallest angle of triangle = 2 × 20° = 40° Greatest angle of triangle = 4 × 20° = 80° ∴ Sum of largest and smallest angle of triangle = 40° + 80° = 120°