$\"\"$

Given that $\"\"$ .

From the figure $\"\"$ are alternate exterior angles.

$\"\"$ (Alternate exterior angles postulate)

From the figure $\"\"$ are corresponding angles.

$\"\"$ (Corresponding angles postulate)

$\"\"$ (Transitive property)

$\"\"$ (From the definition of congruent angles)

$\"\"$ (Substitute $\"\"$ ) $\"\"$

The angle is $\"\"$ .