Copy and complete the proof of the first case of the congruent complements

Copy and complete the proof of the first case of the congruent complements Theorem where two angles are complementary to the same angle.
Given ∠1 and ∠2 are supplements ∠3 and ∠4 are supplements ∠1 ≅ ∠4 Prove ∠2 ≅ ∠3

STATEMENTS I REASONS
I

  1. ∠1 and ∠2 are complements I 1. ? ∠1 and ∠3 are complements I
  2. m∠1 + m ∠ 2= 90° I 2. ? m∠1 + m ∠ 2= 90° I
  3. ? I 3. Transitive Property of Equality
  4. ? I 4. Subtraction Property of Equality
  5. ∠2 ≅ ∠3 I 5. ? I