The **Corresponding Angles Postulate ** states that, when two parallel lines are cut by a transversal, the resulting corresponding angles are congruent.

So, in the figure below, if *l* ||* m*, then 1 2.

The converse is also true; that is, if two lines *l* and *m* are cut by a transversal in such a way that the corresponding angles formed are congruent, then *l* || *m*.