Geometric Question:

angles on opposite sides of the transversal and on the exterior of the parallel lines
The pair of angles on the outside of the two lines cut by the transversal and on alternate sides of the transversal. Alternate exterior angles are congruent if and only if the two lines crossed by the transversal are parallel.
Two angles that are on the outside of the parallel lines and opposite sides of the transversal. These types of angles are always congruent to one another.
The pair of angles on the outside of the two lines cut by the transversal and on alternate sides of the transversal. Alternate exterior angles are congruent if and only if the two lines crossed by the transversal are parallel.
The pair of angles on the outside of the two lines cut by the transversal and on alternate sides of the transversal. Alternate exterior angles are congruent if and only if the two lines crossed by the transversal are parallel. Also: as the name suggests, they're kind of hipster.