|- |bgcolor=#e7dcc3|Edges and vertices||6 |- |bgcolor=#e7dcc3|Schläfli symbols||{6}
t{3} |- |bgcolor=#e7dcc3|Coxeter–Dynkin diagrams||

In geometry, a hexagon is a polygon with six edges and six vertices. A regular hexagon has Schläfli symbol {6}.

Regular hexagon

The internal angles of a regular hexagon (one where all sides and all angles are equal) are all 120° and the hexagon has 720 degrees. It has 6 rotational symmetries and 6 reflection symmetries, making up the dihedral group D₆. The longest diagonals of a regular hexagon, connecting diametrically opposite vertices, are twice its sides in length. Like squares and equilateral triangles, regular hexagons fit together without any gaps to tile the plane (three hexagons meeting at every vertex), and so are useful for constructing tessellations. The cells of a beehive honeycomb are hexagonal for this reason and because the shape makes efficient use of space and building materials. The Voronoi diagram of a regular triangular lattice is the honeycomb tessellation of hexagons.

The area of a regular hexagon of side length $t\backslash ,\backslash !$ is given by $A\; =\; \backslash frac\{3\; \backslash sqrt\{3\}\}\{2\}t^2\; \backslash simeq\; 2.598076211\; t^2.$

The perimeter of a regular hexagon of side length $t\backslash ,\backslash !$ is, of course, $6t\backslash ,\backslash !$, its maximal diameter $2t\backslash ,\backslash !$, and its minimal diameter $t\backslash sqrt\{3\}\backslash ,\backslash !$.

There is no platonic solid made of regular hexagons. The archimedean solids with some hexagonal faces are the truncated tetrahedron, truncated octahedron, truncated icosahedron (of soccer ball and fullerene fame), truncated cuboctahedron and the truncated icosidodecahedron.

. This form only has D₃ symmetry. In this figure, the remaining edges of the original triangle are drawn blue, and new edges from the truncation are red. |valign=top| process: extending the 6 edges of a regular hexagon until they meet at 6 new vertices. |}

, having 3 hexagons around every vertex. |valign=top|