Quadrilateral Lesson for Kids: Definition & Shapes

Instructor: Jennifer Lowery

Jennifer has taught elementary levels K-3 and has master's degrees in elementary education and curriculum/instruction and educational leadership.

You've learned about different types of shapes, but do you know about quadrilaterals? In this lesson, explore the definition of a quadrilateral and find out about many familiar and new types of quadrilaterals!

What Is a Quadrilateral?

How many quarters are in one dollar? How many quarts are in one gallon? Both questions have the same answer: four. Now, do you notice something similar in the words quarter and quart? They both have the same base word, quart, and so does the word quadrilateral. What is a quadrilateral? By now you can probably guess it has something to do with the number four!

A quadrilateral is a flat, two-dimensional shape that has four sides and four corners, or vertices. ('Vertices' is plural for 'vertex.') You probably already know some common quadrilaterals: Squares and rectangles, for instance, both have four sides and four vertices. Let's learn about some other examples and find out about their characteristics.

All of the shapes shown here are quadrilaterals, because each has four sides and four corners.

Beyond Squares and Rectangles

A trapezoid is a type of quadrilateral that is seen less frequently--although you'll notice them in everyday life if you look carefully! This shape has one set of sides that are parallel, which means that those sides are always an equal distance apart, no matter how far you stretch them. (An easy way to remember this is that the two l's in 'parallel' are actually parallel!) The other two sides of the trapezoid are intersecting, which means if they are stretched out, they will eventually cross over each other.

Another type of quadrilateral is a parallelogram. The word might be a tongue twister, but now that you know what 'parallel' means, you'll understand the characteristics of a parallelogram. In this quadrilateral, there are two sets of parallel lines. Keep in mind that there are actually several shapes that can be considered a parallelogram. Some types of parallelograms, for example, look like rectangles that got blown to the side in a wind storm!

A parallelogram has two sets of parallel lines.
quadrilateral shape

A rhombus is a type of shape that is both a quadrilateral AND a parallelogram! Many people would look at this shape and say it is a diamond. But the correct geometry term is rhombus, and it is a quadrilateral that has two sets of parallel sides. All sides of a rhombus are the same length.

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