If a transversal intersects two parallel lines then the sum of interior angles on the same side of the transversal is _____.

The number of angles formed by a transversal of two lines is _____

A transversal intersects two parallel lines. If the measure of one of the angles is $40°$, then the measure of its corresponding angle is _____

In $△ABC, \angle A=76°,\angle B=48°$, $\therefore \angle C=$_____ 

Two parallel lines are intersected by a transversal. If measure of one of the alternate interior angles is $75°$ then the measure of the other angle is _____

Ray $PQ$ and ray $PR$ are perpendicular to each other. Points $B$ and $A$ are in the interior and exterior of $\angle QPR$ respectively. Ray $PB$ and ray $PA$ are perpendicular to each other.

Draw a figure showing all these rays and write a pair of complementary angles.

Prove that, if a line is perpendicular to one of the two parallel lines, then it is perpendicular to the other line.