# How To: Work with polygon geometry names

Watch this video to learn the important polygon names and how to classify different types of polygons.

Polygons are closed plane figures formed by segments. They can be classified based on the number of sides (or angles) they have. A polygon with two sides doe not exist.

A triangle is a polygon with three sides and three angles.

A quadrilateral is a polygon with four sides and four angles.

A pentagon is a polygon with five sides and five angles.

A hexagon is a polygon with six sides and six angles.

A heptagon is a polygon with seven sides and seven angles.

An octagon is a polygon with eight sides and eight angles.

A nonagon is a polygon with nine sides and nine angles.

A decagon is a polygon with ten sides and ten angles.

A dodecagon is a polygon with twelve sides and twelve angles.

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