Question

Can someone help me solve for the missing angle (practice work)

Answer 1

The addition of the three internal angles of a triangle is 180°, then:

∠A + ∠B + ∠C = 180°

∠A + 66° + 42° = 180°

∠A = 180° - 66° - 42°

∠A = 72°

Angle A and angle ? are supplementary, then:

∠A + ∠? = 180°

72° + ∠? = 180°

∠? = 180° - 72°

∠? = 108°