9514 1404 393
Answer:
∠B = ∠C = 138°
∠D = 42°
Explanation:
Angles between the parallel bases are supplementary:
∠B = 180° -∠A = 180° -42° = 138°
Right-side angles are the same measure as their mirrors across the line of symmetry.
∠C = ∠B = 138°
∠D = ∠A = 42°