Octagon

Regular octagon
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 the 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.

[1] Wenninger, Magnus J. (1974), Polyhedron Models, Cambridge University Press, p. 9, ISBN 9780521098595.

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