What defines a trapezoid?

A trapezoid is defined as a quadrilateral that has at least one pair of parallel sides. This characteristic is essential in distinguishing trapezoids from other types of quadrilaterals. In many regions, the definition can be extended to include isosceles trapezoids, which also have non-parallel sides that are of equal length and, consequently, isosceles triangles formed on either end. However, the defining feature remains the presence of one set of parallel sides, which differentiates trapezoids from squares, rectangles, and rhombuses, all of which have either two pairs of parallel sides or other properties.

This understanding is crucial for correctly identifying trapezoids in geometric contexts and solving related problems involving angles, area, and side lengths.