Lines m, l, and n are cut by transversal t. At the intersection of lines m and t, the uppercase left angle is angle 1 and the uppercase right angle is angle 2. At the intersection of lines n and t, the uppercase left angle is angle 3. Lines l, m, and n lie in a plane and are cut by a transversal, t. ∠1 is supplementary to ∠2, and ∠2 is supplementary to ∠3. Which lines, if any, are parallel? What justifies your answer? linear pair postulate