A trapezium, in the context of geometry, is a four-sided figure known as a quadrilateral. By definition, a trapezium has exactly one pair of parallel sides. This specific characteristic differentiates it from other quadrilaterals like parallelograms, rectangles, or squares, which have two pairs of parallel sides. The steps to determine which description fits a trapezium are as follows:
- Identify that in a trapezium, there should exactly be one pair of opposite sides that are parallel.
- Contrast this with a scenario where both pairs of opposite sides could be parallel—this would make the figure a parallelogram.
- Recognize the definition: "Two opposite sides are parallel and two opposite sides are non-parallel" aligns with having only one pair of parallel sides.
Matching the given options with these characteristics, the correct definition of a trapezium is: "Two opposite sides are parallel and two opposite sides are non-parallel."