Question

A quadrilateral ABCD is a trapezium if ______.

Options

• AB = DC

• AD = ВС

• ∠A + ∠C = 180°

• ∠B + ∠C = 180°

Answer 1

A quadrilateral ABCD is a trapezium if ∠B + ∠C = 180°.

Explanation:

For a quadrilateral to be a trapezium, at least one pair of opposite sides must be parallel. If ∠B + ∠C = 180°, these interior angles on the same side of transversal BC are supplementary, which proves that side AB is parallel to side DC.