Apair of parallel lines is cut by a transversal, as shown below: a pair of parallel lines is cut by a transversal. the interior angle made on the left by the intersection of the upper parallel line and the transversal is labeled as x. the interior angle made on the right by the intersection of the lower parallel line and the transversal is labeled as y. which of the following best represents the relationship between angles x and y? x = y x = 180° − y y = 180° − x x = 2y