Step-by-step explanation:
PQ and RS are not parallel, because the intersection angles at A and B are different.
if the 2 lines were parallel, then one would mimmick perfectly the attributes and behavior in their intersections with another line.
so, the angle would be equal.
that is the point of being parallel : each line acts as if it were the other line, they are just shifted a little bit, but not rotated.
