Question

what reason can be used to justify the following statements: ∠1≅∠2 and ∠3≅∠4
complements of congruent angles are congruent.
corresponding angles are congruent.
vertical angles are congruent.
supplements of congruent angles are congruent.

Explanation:

Angles ∠1 and ∠2, as well as ∠3 and ∠4, are pairs of vertical angles formed by the intersection of lines. By the vertical - angles theorem, vertical angles are congruent.

Answer:

Vertical angles are congruent.