Question

What special name can be given to a quadrilateral $PQRS$ if $\angle P+\angle S={180}^{\circ }$?

Answer 1

Given, In quadrilateral $PQRS$, $\angle P+\angle S={180}^{\circ }$

$\Rightarrow PQ\parallel SR$

Since, In a quadrilateral if one pair of opposite sides are parallel then it is called a Trapezium.

According to question, in quadrilateral $PQRS$, one of the pair of opposite sides are parallel.

Hence, quadrilateral $PQRS$ is a Trapezium.