If ∠ 1 and ∠ 2 are congruent then the converse of the Alternate Exterior Angles Theorem guarantees that lines x and z are parallel.
The measure of congruent angles are equal.
Since it is given that m∠ 1=110^(∘), the measure of ∠ 2 must also be 110^(∘) for lines x and z to be parallel.
