What is the relationship between alternating interior angles?

The correct answer highlights a fundamental property of alternating interior angles that occurs when two parallel lines are intersected by a transversal. Alternating interior angles are defined as pairs of angles that are located on opposite sides of the transversal and are situated between the two parallel lines. This positioning is crucial since it leads to the conclusion that these angles are congruent; that is, they have the same measure.

In geometry, when two parallel lines are intersected by a transversal, the angles formed exhibit specific relationships, and recognizing these relationships is essential for solving problems related to angle measures and the properties of parallel lines.

The other options reflect common misconceptions about angles formed by transversals. They either misplace the angles in relation to the transversal and parallel lines or misunderstand the angles' adjacency, which is not characteristic of alternating interior angles. Understanding the correct positioning reinforces the concept that when you encounter a transversal intersecting parallel lines, the relationship between angles can provide valuable information for proofs and calculations in geometry.