Question

In th given figure, OB is perpendicular to OA and$\angle BOC={49}^{\circ }.$ Find $\angle AOD.$

Answer 1

In the given figure, OB is perpendicular to OA.
So, ∠AOB = 90°
Given that ∠BOC = 49°, we can say that ∠COA = ∠AOB - ∠BOC = 90° - 49° = 41°
Now ∠COA and ∠AOD form a linear pair, i.e. the sum of these two angles is 180°.
So, the required angle ∠AOD = 180° - ∠COA = 180° - 41° = 139°