The short answer to “what is a quadrilateral?” is that it is a four-sided polygon. In other words it is four-sided, two-dimensional enclosed shape with straight sides.
Your children will learn (typically in 5th Grade) that there are many different types of quadrilaterals and they can be arranged in a hierarchy based on their properties.
Discuss the relationship between the quadrilaterals with your children. Follow the arrows down to see how certain ones are also special types of others as they exhibit all their properties. For example, a square is a special type of rectangle. Indeed a square can be said to be a special case of all the other quadrilaterals shown in the table.
The table shows different types of special quadrilaterals arranged in a hierarchy.
Quadrilateral Properties and Hierarchy
Follow the arrows down (or up if your prefer) the table to view the various categories and sub-categories.
Square
A Square is a quadrilateral with equal-length sides forming four right-angles.
| A square is also a special type of |
… and it is also a special type of |
| Rhombus | Rectangle |
 |
 |
| A Rhombus is a Quadrilateral in which opposite sides are parallel and all four sides are of equal length. | A rectangle is a quadrilateral with four right-angles and opposite sides that are parallel. |
| A Rhombus is also a special type of |
… and it is also a special type of |
A Rectangle is also a special type of |
| Kite | Parallelogram |
 |
 |
| A Kite is a Quadrilateral in which the sides can be grouped into two pairs of adjacent equal-length sides. | A Parallelogram is a quadrilateral in which each of the two pairs of opposite sides are parallel. |
| A Parallelogram is* also a special type of |
|
| Trapezoid | |
 A Trapezoid is a Quadrilateral in which two of the sides are parallel. |
|
| A Kite is also a special type of |
A Trapezoid is also a special type of |
Quadrilateral
A Quadrilateral is a polygon with four sides.
* Using the Inclusive (not the Exclusive one) definition of a Trapezoid
Worksheets
Click the links below and get your children to try both worksheets.
You can also try a hands-on activity with this worksheet to show that there are 360° in a quadrilateral.
