#### Answer

1. Given
2. Corresponding angles
4. $\angle$3 and $\angle$4
5. (answer given in problem)
6a. l$\parallel$n
6b. Corresponding angles postulate

#### Work Step by Step

1. Given statements are always defined
2. Corresponding angles are angles formed from two parallel lines cut by a transversal. Because l$\parallel$m and line t is the transversal, $\angle$1 and $\angle$2 are are corresponding angles
4. Given
6. The Corresponding angles postulate states if a traversal (line t) intersects two parallel lines (refer to given), then they are congruent. Since $\angle$1 and $\angle$4 are corresponding angles, this means l$\parallel\$n.