Match the reasons with the statements in the proof if the last line of the proof would be
6. ∠1 and ∠7 are supplementary by definition.
Given: s || t
Prove: 1, 7 are supplementary


1. Substitution
2. Exterior sides in opposite rays.
3. Given
4. If lines are ||, corresponding angles are equal.
5. Definition of supplementary angles.


s||t
∠5 and ∠7 are supplementary.
m∠5 + m∠7 = 180°
m∠1 = m∠5
m∠1 + m∠7 = 180°