Math Homework. Do It Faster, Learn It Better.

Alternate Exterior Angles

The term alternate exterior angles is often used when two lines are cut by a third line, a transversal .

Two parallel lines cut by a transversal n, with angles labeled 1 through 8

In the figure above, line t is a transversal cutting lines k and l , and there are two pairs of alternate exterior angles:

1 and 7

4 and 6

The Alternate Exterior Angles Theorem states that if k and l are parallel , then the pairs of alternate exterior angles are congruent . That is,

1 7 and 4 6 .

The converse of this theorem is also true.