Question

Two straight lines AC and BD intersect each other at a point O.

If



BOC =75˚. Find



AOD. [1]

A B

O

D C​

Answer 1

Answer:

BOD = ∠AOC

(Vertically opposite angles are equal)

∴ ∠BOD =50°

(ii) ∠AOD

∠AOD + ∠BOD = 180°

∠AOD + 50° = 180° [From (i)]

∠AOD = 180°-50°

∠AOD = 130°

(iii) ∠BOC = ∠AOD

(Vertically opposite angles are equal)

∴ ∠BOC = 130°