What Is a Quadrilateral That Is Not a Parallelogram?

Trapezoids and kites are shapes that are quadrilaterals but not parallelograms. A quadrilateral is a two-dimensional shape with four straight sides, although the sides can cross each other.

In a quadrilateral, some angles can be concave instead of convex. The inside angles add up to 360 degrees, no matter how it is shaped. Some quadrilaterals have special properties, like squares. The sides of a square are all equal, and each angle inside is a right angle.

A parallelogram is a shape with two sets of sides that run parallel. Therefore, many unnamed shapes are also quadrilaterals without being parallelograms. That is, some shapes do not have special properties, like equal sides, so they do not have specific names; for instance, a shape that has four unequal sides is a quadrilateral but not a parallelogram.