Final answer:
The alternate exterior angles formed when two parallel lines are cut by a transversal are congruent, which means they have the same measure.
Step-by-step explanation:
When two parallel lines are cut by a transversal, the alternate exterior angles are congruent. This is a fundamental concept in geometry that deals with the relationships between angles formed by two parallel lines and a transversal.
In this scenario, alternate exterior angles are on opposite sides of the transversal and outside of the two parallel lines. According to the properties of parallel lines cut by a transversal, these angles are equal in measure. For example, if two parallel lines are cut by a transversal and one alternate exterior angle is 70 degrees, the other alternate exterior angle will also be 70 degrees, demonstrating their congruence.
The correct answer to the question is: D) Congruent.