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

Definition

By two lines and a transversal,
two pairs of alternate exterior angles are formed.

∠1 and ∠1'
∠2 and ∠2'

Formula

Formula

Alternate exterior angles in parallel lines
are congruent.

m∠1 = m∠1'
m∠2 = m∠2'

Example

Example

Solution

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.