| Regular octagon | |
|---|---|
 A regular octagon | |
| Type | Regular polygon |
| Edges and vertices | 8 |
| Schläfli symbol | {8}, t{4} |
| Coxeter–Dynkin diagrams |     |
| Symmetry group | Dihedral (D8), order 2×8 |
| Internal angle (degrees) | 135° |
| Properties | Convex, cyclic, equilateral, isogonal, isotoxal |
| Dual polygon | Self |
In geometry, an octagon (from Ancient Greek ὀκτάγωνον (oktágōnon) 'eight angles') is an eight-sided polygon or 8-gon.
A regular octagon has Schläfli symbol {8} [1] and can also be constructed as a quasiregular truncated square, t{4}, which alternates two types of edges. A truncated octagon, t{8} is a hexadecagon, {16}. A 3D analog of the octagon can be the rhombicuboctahedron with the triangular faces on it like the replaced edges, if one considers the octagon to be a truncated square.
- ^ Wenninger, Magnus J. (1974), Polyhedron Models, Cambridge University Press, p. 9, ISBN 9780521098595.