Answer:
20. ∠ADB and ∠BDC
22. ∠ADC and ∠FDE or ∠ADE and ∠FDC
Step-by-step explanation:
You want a pair of complementary angles, and a pair of vertical angles as shown in the figure.
20. Complementary
Complementary angles total 90°. The two angles that are created from the division of the marked right angle will total 90°. Those angles are ...
∠ADB and ∠BDC
22. Vertical
Vertical (or "opposite") angles are formed by the intersection of two straight lines. The point of intersection is their common vertex. The angles are formed by opposite rays, are not adjacent, and have no interior points in common.
Where lines cross, two pairs of vertical angles are formed. In the given figure, those two pairs are ...
- ∠ADC and ∠EDF
- ∠ADE and ∠CDF
