how to I fiqure this problem out in geometry

Question

m<abc=42, m<cbd=35 find m<abd

Answer 1

∠abc and ∠cbd have a common vertex (b) and a common side (bc). They are adjacent angles.

m∠abd = m∠abc + m∠cbd = 42° + 35° = 77°

Answer 2

The name of this property is the angle sum postulate. You should remember this term for use in proofs.