| Regular hendecagon | |
|---|---|
 A regular hendecagon | |
| Type | Regular polygon |
| Edges and vertices | 11 |
| Schläfli symbol | {11} |
| Coxeter–Dynkin diagrams |    |
| Symmetry group | Dihedral (D11), order 2×11 |
| Internal angle (degrees) | ≈147.273° |
| Properties | Convex, cyclic, equilateral, isogonal, isotoxal |
| Dual polygon | Self |
In geometry, a hendecagon (also undecagon[1][2] or endecagon[3]) or 11-gon is an eleven-sided polygon. (The name hendecagon, from Greek hendeka "eleven" and –gon "corner", is often preferred to the hybrid undecagon, whose first part is formed from Latin undecim "eleven".[4])
- ^ Haldeman, Cyrus B. (1922), "Construction of the regular undecagon by a sextic curve", Discussions, American Mathematical Monthly, 29 (10), doi:10.2307/2299029, JSTOR 2299029.
- ^ Cite error: The named reference
loomiswas invoked but never defined (see the help page). - ^ Brewer, Ebenezer Cobham (1877), Errors of speech and of spelling, London: W. Tegg and co., p. iv.
- ^ Hendecagon – from Wolfram MathWorld