If two parallel lines are intersected by a transversal,then interior angles on the same side of the transversal are $\ldots \ldots . . .$

If two parallel lines are intersected by a transversal,then each pair of corresponding angles are...........

$A$ transversal intersects two lines in such a way that the two interior angles on the same side of the transversal are equal. Will the two lines always be parallel? Give reason for your answer.

Can a triangle have all angles less than $60^{\circ}$? Give reason for your answer.

Prove that through a given point,we can draw only one perpendicular to a given line.

In the given figure,if $AB \parallel CD$,$\angle AXY = 80^{\circ}$ and $\angle XZD = 140^{\circ}$,then find $x$ and $y$.