# Alternate Exterior Angles: in Parallel Lines

How to solve the alternate exterior angles in parallel lines: formula, 1 example, and its solution.

## Alternate Exterior Angles

By two lines and a transversal,

two pairs of alternate exterior angles are formed.

∠1 and ∠1'

∠2 and ∠2'

## Formula

Alternate exterior angles in parallel lines

are congruent.

m∠1 = m∠1'

m∠2 = m∠2'

## Example

Solution

Solution (Detail)

The given angles are

alternate exterior angles in parallel lines.

So the given angles are congruent.

So [8x + 10] = [74].

Move +10 to the right side.

Then 8x = 64.

Divide both sides by 8.

Then x = 8.

So x = 8.