Final answer:
The angles in question are called alternate exterior angles, which are congruent when the lines intersected by the transversal are parallel.
Step-by-step explanation:
The pairs of nonadjacent angles formed when a transversal intersects two lines so that they lie on opposite sides of the transversal and outside the lines are called alternate exterior angles. When the lines are parallel, each pair of alternate exterior angles are equal to each other. They are part of the various angle pairs created by a transversal, including corresponding angles, alternate interior angles, and same-side (consecutive) interior angles.
For example, if a transversal cuts across two parallel lines, we observe that the alternate exterior angles are congruent, which means they have the same measure. This property is often used to prove that lines are parallel or to find missing angle measures in geometric problems.