Question

in which figure do $\angle 1$ and $\angle 2$ represent a pair of alternate exterior angles?

Explanation:

Alternate exterior angles are defined as a pair of angles that lie outside the two parallel lines, on opposite sides of the transversal, and are non-adjacent. We check each figure:

1. Top-left: ∠1 and ∠2 are on the same side of the transversal, so not alternate exterior.
2. Top-right: ∠1 and ∠2 are on opposite sides of the transversal, outside the two parallel lines, matching the definition.
3. Bottom-left: ∠1 and ∠2 are interior angles relative to the parallel lines, so not exterior.
4. Bottom-right: ∠1 and ∠2 are on the same side of the transversal, so not alternate exterior.

Answer:

The top-right figure (second figure in the top row) where ∠1 and ∠2 are on opposite sides of the transversal, outside the pair of parallel lines.