Given: <1 and <2 are supplementary angles Prove: l || m

Question

STATEMENT                               REASON

1.∠1 and ∠2 are supplementary angles                       1. Given

2. m∠1 + m∠2 = 180°                                               2.______

3. ∠1 and ∠3 are supplementary angles                      3. Exterior sides in opposite rays

4.________                               4._________

5. m∠1 + m∠2 = m∠1 + m∠3                                     5._________

6._________                               6._________

7. l || m                                                                   7.__________

Answer 1

So >2=>3. Put >1 in there too; each one measures 90°.

What do you mean by #7?