Polygon might seem like a tricky word at first, but you’re actually pretty familiar with what they are. Squares, rectangles, and triangles are all polygons! A polygon is a shape made of three or more straight lines that surround a closed space. If you had three lines that did not make a triangle but instead looked like the letter “N,” that would not be a polygon because the lines don’t close a space. A space is closed when it is entirely surrounded by lines.
A polygon with three sides is a triangle. A polygon with four sides is a square or a rectangle.
A polygon with five sides is called a pentagon. When there are six sides, the shape is a hexagon. When there are seven sides, it’s a heptagon.
Eight sides make an octagon. Nine sides make a nonagon. Ten sides, make a decagon!

Exploration
The Search for Polygons!Polygons are around us all the time. Sometimes we just don’t think about them. What polygons do you see when you’re riding in a car? What shape is a yield sign? What shape is a stop sign?
What polygons do you see when playing baseball? What shape is first base? What shape is the pitching rubber or pitcher’s plate? What shape is home plate?
What shapes do you find on a soccer ball? What shapes are the stars on an American flag? What shape is the floor in your bedroom?
Polygons are everywhere! Can you draw a polygon that has a lot of sides? Ask a grownup if there is a name for the polygon you drew? If there isn’t one, what would you call it?