1. Proving Lines are Parallel
Section 3-4
Proving Lines are Parallel

2. Converse of Corresponding Angles postulate
If two lines are cut by a transversal so that corresponding angles are congruent, then the lines are parallel.

3. 1 2 j k
j║k
therefore

4. Converse of Alternate interior Angles theorem
If two lines are cut by a transversal so that alternate interior angles are congruent, then the lines are parallel.

5. j k 3 4
If , then
j║k.

6. Converse of consecutive interior Angles theorem
If two lines are cut by a transversal so that consecutive interior angles are supplementary, then the lines are parallel.

7. j k 5 6
If , then
j║k.

8. Converse of Alternate exterior Angles theorem
If two lines are cut by a transversal so that alternate exterior angles are congruent, then the lines are parallel.

9. j k 7 8
If , then
j║k.