Polygons

A polygon is a flat, closed shape made only of straight lines. The sides must connect to form a complete shape with no openings. Triangles, squares, and hexagons are all polygons. Circles are not polygons because they have no straight sides. Polygons are a big part of geometry.

Naming Polygons

Polygons are named by how many sides they have. A triangle has 3 sides. A quadrilateral has 4 sides. A pentagon has 5 sides, like the shape of a house. A hexagon has 6 sides, like a honeycomb cell. An octagon has 8 sides, like a stop sign.

Regular and Irregular

A regular polygon has all sides and angles equal, like a square or an equilateral triangle. An irregular polygon has sides or angles that are not all the same. Both kinds are still polygons. You can find polygons in buildings, games, traffic signs, and artwork.

Fun Facts

• The word polygon comes from Greek words meaning many angles.
• A polygon with 100 sides is called a hectogon.
• Stop signs are octagons, which means they have 8 sides.

Did You Know?

The more sides a regular polygon has, the more it starts to look like a circle.