What is a polygon?

A polygon is any shape with three or more straight sides. A lot of shapes you know are polygons, like triangles, squares, and rectangles. The sides on a polygon cannot cross one another (for example, an hourglass shape is not a polygon).

A corner where two sides on a polygon meet is also called the vertex (we call them vertices when talking about several of them).

A couple of vertices were labeled in the picture above. Can you identify more of them on other shapes?

Every polygon has a special name based off of how many sides they have. You already know about triangles (three-sided polygons) and many types of quadrilaterals, or four-sided polygons (like squares, rectangles, and trapezoids). But what about polygons with five sides? Six sides? Seven sides or more? Here are the polygons you should know how to name (up to ten sides):

Polygons don't have to look exactly like the ones shown above. For example, any seven-sided shape is still called a heptagon as long as its sides are straight and do not cross one another.

Sometimes, you can cut up polygons or combine polygons to create shapes with different numbers of sides. You can even make different types of polygons from the same shape(s), depending on where you cut or stick them together.