A polygon is understood to be that geometric shape that is composed of many sides, and they may be arranged in a regular or irregular way. The word polygon comes from the Greek and means "many angles". Polygons are flat shapes that are also closed and normally have from three sides onwards (triangles or squares being different types of polygons).
Polygons are made up of several sides, which are those that give a limit to the figure and mark its surface, in addition to defining them in space. The sides of a polygon are always closed, so this type of geometric figures can never be open. When two sides meet or join at a point, an angle is formed that will be a characteristic and distinctive element of this type of specific polygon, and can be larger or lower depending on the type of side union that is generated. This angle can never be 180 degrees however, because if it were, it would form a new segment or line.
Other elements that make up the polygon are the diagonals, those straight lines that join two or more non-contiguous vertices, the perimeter or sum of the sides that compose it, the internal and external angles. On the other hand, regular polygons, that is, composed of similar or balanced sides, have a clearly marked center and an apothem or the line that joins the center with one of its sides.
According to the number of sides they have, the polygons take different names. Thus, the simplest or most basic are the triangles (the first polygons that can be formed since there are no polygons with one or two sides), the quadrangle and the pentagon, respectively with three, four and five sides. Then it is followed by hexagons, heptagons, octagons, eneagons and decanogos and then continue infinitely. A megagon is, for example, a figure that has a million sides.