Which angle(s) is/are congruent?

In a pair of parallel lines cut by a transversal, corresponding angles and alternate interior angles are congruent. This means if you have two lines parallel to each other and a transversal crossing through them, the angles that occupy the same relative position at each intersection with the transversal (like the top left corner of each intersection) will be congruent. This is known as the Converse of the Corresponding Angle Postulate! To put this into practice, imagine you're trying to make sure a pair of wooden slats are parallel for a DIY project. Measure one angle from each intersection – if they're the same, congratulations! You’ve got those slats perfectly parallel, all thanks to the regularity of congruence in those angles!