How do you prove the AIP theorem?
(Alternate Interior Angles and Parallel theorem) I already know you can prove the CAP theorem(Corresponding Angles and Parallel theorem), and the SAP theorem from it,but I don't know how to prove the AIP as a start.
The AIP Theorem.
Given: If transversal $n$ intersects two lines in such a way that a pair of alternate exterior angles are equal, then the two lines are parallel.
Statement: Line $n$ intersects lines $l$ and $m$ such that a pair of alternate exterior angles are congruent.