Answer:
Part A - D:8
Part B - C:140°
Solving/Reasoning:
Part A: Vertical angles are always congruent.
Part B: If angles are supplementary, they need to equal 180 when added together. Since we know angle A is 40, we can subtract it from 180 and figure out what is left over that should be angle B.
40+B=180
B=180-40
B=140
