What do alternating exterior angles consist of?

Alternating exterior angles are formed when a transversal intersects two parallel lines. These angles lie on opposite sides of the transversal and are positioned outside the parallel lines. Their defining characteristic is that they are not next to each other (not adjacent) and they are not located between the parallel lines (which would place them as interior angles).

When identifying alternating exterior angles, you can visually confirm this by observing that if you have two lines with a transversal, the angles that are exterior and on opposite sides of the transversal will be equal in measure if the lines are indeed parallel. This specific positioning of the angles is why the identification of them as being on opposite sides of the transversal is correct.