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!