3.1.3 Proving that Lines are Parallel

Question 1

Converse of the Corresponding Angles Postulate

Answer 1

If two coplanar lines are cut by a transversal so that a pair of corresponding angles are congruent, then the two lines are parallel.

Question 2

Parallel Postulate

Answer 2

Through a point P not on line L, there is exactly one line parallel to L.

Question 3

Converse of the Alternate Interior Angles Theorem

Answer 3

If two coplanar lines are cut by a transversal so that a pair of alternate interior angles are congruent, then the two lines are parallel.

Question 4

Converse of the Alternate Exterior Angles Theorem

Answer 4

If two coplanar lines are cut by a transversal so that a pair of alternate exterior angles are congruent, then the two lines are parallel.

Question 5

Converse of the Same-Side Interior Angles Theorem

Answer 5

If two coplanar lines are cut by a transversal so that a pair of same-side interior angles are supplementary, then the two lines are parallel.