Answer:
The answer is ASA
Explanation:
In order to determine the correct reason, we have to know which angles and sides are the same.
According to the attached image:
- we know that side AD has the same length that side BC.
- we know that angles 2 and 4 are the same. The same situation for angles 1 and 2. The reason is if lines are parallel, then alternate interior angles are the same.
- ΔADM has the order: ∠2 -side AD-∠1
- ΔBCM has the order: ∠4 -side BC-∠3
Therefore, if ∠2=∠4; AD=BC; ∠1=∠3, the proof that the triangles are congruent is ASA.