**Tetragon**

**Tetragon** is a plane figure with four straight sides and angles.

In geometry a** quadrilateral** is a four-sided polygon, having **four edges (sides)** and **four corners (vertices)**.

It is also called a **tetragon**, derived from Greek “tetra” meaning “four” and “gon” meaning “corner” or “angle”

The only **regular **(all sides equal and all angles equal) quadrilateral is a **square**. So all other quadrilaterals are **irregular**.

https://en.wikipedia.org/wiki/File:Six_Quadrilaterals.svg

https://en.wikipedia.org/wiki/File:Quadrilaterals.svg

In daily life we think of a square as not being a rectangle but in mathematics it is.

A square is a rectangle with equal sides.