Statement |
| Reason |
∠1, ∠2, ∠3, and ∠4 formed by two intersecting segments. |
| Given |
∠1 and ∠2 form a linear pair. |
| Definition of linear pair |
∠2 and ∠3 form a linear pair. |
| Definition of linear pair |
m∠1 + m∠2 = 180° |
| Linear Pair Postulate |
m∠2 + m∠3 = 180° |
| Linear Pair Postulate |
m∠1 + m∠2 = m∠2 + m∠3 |
| Substitution Property of Equality |
m∠1 = m∠3 |
| Subtraction Property of Equality |