1. JK || ML
1. given
2. ∠JKN and ∠MLN are alternate interior angles
2. def. of alternate interior angles
3. ∠JKN ≅ ∠MLN
3. alternate interior angles theorem
4. ∠KNJ and ∠LNM are vertical angles
4. def. of vertical angles
5. ∠KNJ ≅ ∠LNM
5. vertical angles are congruent
6. △JKN ~ △MLN
6. AA similarity theorem