Here’s the completed two-column proof with the missing statements filled in:
Statements | Reason --- | ---
- ∠1 and ∠2 are supplementary | 1. Given
- m∠1 + m∠2 = 180 | 2. Supplementary angles add up to 180.
- ∠2 and ∠3 are supplementary | 3. Given
- m∠2 + m∠3 = 180 | 4. Supplementary angles add up to 180.
- m∠1 + m∠2 = m∠2 + m∠3 | 5. Transitive Property of Equality
- m∠1 = m∠3 | 6. Subtraction Property of Equality
- ∠1 ≅ ∠3 | 7. Definition of Congruent Angles
This proof demonstrates the relationships between the angles based on their measures and utilizes properties of equality and definitions related to congruence.