Answer:
(a) ∠1 and ∠5
Explanation:
Complementary angles are angles whose measures total 90°. The angles do not have to be adjacent.
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In this geometry, we can see that angles 1 and 2 are complementary, as are angles 4 and 5, since their respective sums are right angles. Angles 2 and 5 are vertical angles, so have the same measure.
∠1 + ∠2 = 90° . . . . . . adjacent angles that total a right angle
∠1 +∠5 = 90° . . . . . substitute ∠5 for ∠2, since measures are equal
This means angles 1 and 5 are complementary.