# Question: proofplease be descriptive two lines are parallel and we have...

###### Question details

PROOF-PLEASE be descriptive.

Two lines are parallel and we have a non-perpendicular transversal. We assume conjecture 1 holds, which states that same-side interior angles are supplementary.

We **cannot** use alternate interior angles are
congruent, alternate exterior angles are congruent, corresponding
angles are congruent.

Prove: For any set of parallel lines in the plane, alternate interior angles are congruent.