Let O be the in-centre of a triangle ABC and D be a point on the side BC of ΔABC, such that OD ⊥ BC. If ∠BOD = 15°, then ∠ABC = ?

Answer: Option C

According to question,

Given : ∠BOD = 15°
∴ ∠BDO + ∠DOB + ∠DBO = 180°
∠DBO = 75°
∠ABC = 2 × ∠DBO
∠ABC = 2 × 75°
∠ABC = 150°