∠BAO = x = ?GHong14 wrote:
∠BOA = x , as AB = CO = OB (radius of the semi-circle)
∠OBC = ∠BAO + ∠BOA = 2x
∠OCB = ∠OBC = 2x (As OC = OB)
Statement 1:
∠COD = 60
Since, ∠BOA + ∠BOC+∠COD = 180
=> x + (180-4x) + 60 = 180 -- Sufficient
Statement 2:
∠BCO = 40 = 2x -- Sufficient
Hence, D
