What makes a quadrilateral a trapezoid

This may seem odd, as in daily life we think of a square as not being a rectangle Oh Yes! A quadrilateral is a polygon.

In fact it is a 4-sided polygon, just like a triangle is a 3-sided polygon, a pentagon is a 5-sided polygon, and so on. Now that you know the different types, you can play with the Interactive Quadrilaterals. Example: A parallelogram with: all sides equal and angles "A" and "B" as right angles is a square! Example: a square is also a rectangle. So we include a square in the definition of a rectangle. This seems to have been most important in earlier times.

The advantage of the inclusive definition is that any theorem proved for trapezoids is automatically a theorem about parallelograms. This fits best with the nature of twentieth-century mathematics. It is possible to function perfectly well with either definition. Sufficient - The qualities of B sufficiently describe A. Some crazy examples of quadrilaterals:. This means that a trapezoid is too specific of a quadrilateral that merely having the quality of "quadrilateral" does not guarantee the quality of "trapezoid".

Overall, a trapezoid is a quadilateral, but a quadrilateral doesn't have to be a trapezoid. Why is a trapezoid a quadrilateral, but a quadrilateral is not always a trapezoid? Geometry Quadrilaterals Quadrilaterals. Truong-Son N. Nov 12, Are the qualities of a quadrilateral sufficient to describe a trapezoid? Well, from these questions we have: No.