When 2 lines are parallel, corresponding angles are equal. Given angles in the first image are corresponding angles. So z = 120∘.
When 2 lines are parallel, alternate interior angles are equal. Given angles in the second image are alternate interior angles. So z = 60∘.
Given angles in the third image are co-interior. Co-interior angles are supplementary.
∴ z + 70∘ = 180∘
⇒ z = 110∘