Definition of Polygon

A polygon is a plane figure or two-dimensional shape with three or more sides.

A triangle and square are polygons, as well as more complicated shapes, for example, a ten-sided decagon.

Polygons are named according to the number of sides and angles they have.

Regular and Irregular Polygons:

A polygon is called a regular polygon if all its sides are equal, while irregular polygons have unequal sides and angles.

The interior angle of a convex polygon is strictly less than 180°. A polygon with at least one interior angle greater than 180° is called a non-convex polygon or concave polygon.

Convex and Concave Polygons:

A concave polygon will always have at least one reflex or reentrant interior angle, that is, an angle with a measure that is between 180° and 360°.

Concave polygons cannot be regular polygons, while convex angles can be regular and irregular.