Question

In the following figure, find the values of a, b and c.

Answer 1

In figure,

∠A + ∠B + ∠C = 180°  ...[Sum of all angles of a triangle is 180°]

⇒ 90° + a + 70° = 180°  ...[∵ ∠A = 90° and ∠C = 70°, from the figure]

⇒ a + 160° = 180°

⇒ a = 180° – 160° = 20°

Since, c is an exterior angle of ΔABD.

∴ ∠c = a + 30° = 20° + 30° = 50°   ...[∵ Exterior angles = Sum of opposite interior angles]

Also, b is an exterior angle of ΔADC

∴ ∠b = 60° + 70° = 130°  ...[∵ Exterior angles = Sum of opposite interior angles]