In ΔABC, D is a point on AC such that AB = BD = DC. If ∠BAD = 60°, then the measure of ∠B is?
Answer & explanation
Correct answer: option 2
∠BAD = ∠BDA (because AB = BD)
and ∠BDA = ∠CBD + ∠BCD = x + x = 2x
2x = 60°
x = 30°
∠ABD = 180° - 60° - 60° = 60°
∠B = 60° + x = 60° + 30° = 90°