Given: line p is parallel to line r. prove: ∠1 is supplementary to ∠7. statement reason 1. line p is parallel to line r. 1. 2. ∠2≅∠7 2. 3. m∠2=m∠7 3. 4. ∠1 and ∠2 form a linear pair. 4. 5. ∠1 is supplementary to ∠2. 5. 6. m∠1+m∠2=180° 6. 7. m∠1+m∠7=180° 7. 8. ∠1 is supplementary to ∠7. 8.

Given,

p and r are parallel lines,

We have to prove that : ∠1 is supplementary to ∠7.

Thus, the column prove would be,

        Statement                                             Reason

1. Line p is parallel to line r.                 1. Given

2. ∠2≅∠7                                             2. Exterior alternate angle theorem,

3. m∠2=m∠7                                        3. Property of congruence,

4. ∠1 and ∠2 form a linear pair.          4. Adjacent angle on straight line,

5. ∠1 is supplementary to ∠2             5. Linear pair postulate

6. m∠1+m∠2=180°                                6. Supplementary angle property

7. m∠1+m∠7=180°                                 7. Substitution property

8. ∠1 is supplementary to ∠7               8. Supplementary angle property

step-by-step explanation:

a and d