If the three angles of any right triangle sum to two right angles, then through a given point, only one line can be drawn parallel to a given line. Draw the perpendicular PQ from the point P to the given line l. Construct the line r through P, perpendicular to PQ. If ∠1 ∠2, then the oars are parallel. Substitute 9 for xin each expression: m∠1 = 3x+ 13 = 3 ( 9)+ 13 = 40° Substitute 9 for x in each expression. m∠2 = 5x- 5 = 5 ( 9)m- 5 = 40° ∠1 =m 2, so 2. The corresponding angles are congruent, so the oars are parallel by the Converse of the Corresponding Angles Postulate.