A trapezium is a closed, two-dimensional shape with two sides that run parallel to each other. It has four sides and four points where they meet. The parallel sides of a trapezium are called bases, and the sides that aren't parallel are called legs. There are three main kinds of trapeziums: The Scalene Trapezium has different-sized sides and angles. As you can see in the picture below, the scalene trapezium is just a trapezoid.