Jump to content

Monogon

From Wikipedia, the free encyclopedia
Monogon
On a circle, amonogonis atessellationwith a single vertex, and one 360-degree arc edge.
TypeRegular polygon
Edgesandvertices1
Schläfli symbol{1} orh{2}
Coxeter–Dynkin diagramsor
Symmetry group[ ], Cs
Dual polygonSelf-dual

Ingeometry,amonogon,also known as ahenagon,is apolygonwith oneedgeand onevertex.It hasSchläfli symbol{1}.[1]

In Euclidean geometry[edit]

InEuclidean geometryamonogonis adegeneratepolygon because its endpoints must coincide, unlike any Euclidean line segment. Most definitions of a polygon in Euclidean geometry do not admit the monogon.

In spherical geometry[edit]

Inspherical geometry,a monogon can be constructed as a vertex on agreat circle(equator). This forms adihedron,{1,2}, with twohemisphericalmonogonal faces which share one 360° edge and one vertex. Its dual, ahosohedron,{2,1} has twoantipodalvertices at the poles, one 360°luneface, and one edge (meridian) between the two vertices.[1]


Monogonaldihedron,{1,2}

Monogonalhosohedron,{2,1}

See also[edit]

References[edit]

  1. ^abCoxeter,Introduction to geometry,1969, Second edition, sec 21.3Regular maps,p. 386-388
  • Herbert Busemann,The geometry of geodesics. New York, Academic Press, 1955
  • Coxeter, H.S.M;Regular Polytopes(third edition). Dover Publications Inc.ISBN0-486-61480-8