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 divided into 2 parts by a slanting line. one part of this angle is labeled as x, and the other part is labeled as 30 degrees. the interior angle made on the right by the intersection of the lower parallel line and the transversal is labeled as 75 degrees.