Question

$ABCD$ is a quadrilateral with $\angle A={80}^{\circ },\angle B={40}^{\circ },\angle C={140}^{\circ },\angle D={100}^{\circ }$.Is $ABCD$ is a trapezium?Justify your answer.

Answer 1

Using angle-sum property, we have

$\angle A+\angle B+\angle C+\angle D={360}^{\circ }$

$\Rightarrow {80}^{\circ }+{40}^{\circ }+{140}^{\circ }+{100}^{\circ }={360}^{\circ }$

Hence, $ABCD$ is a trapezium.