Equiangular polygon Equiangular polygon In Euclidean geometry, an equiangular polygon is a polygon whose vertex angles are equal. If the lengths of the sides are also equal (that is, if it is also equilateral) then it is a regular polygon. Isogonal polygons are equiangular polygons which alternate two edge lengths. The only equiangular triangle is the equilateral triangle. Rectangles, including the square, are the only equiangular quadrilaterals (four-sided figures). For a convex equiangular "n"-gon each internal angle is 180(1-2/n)°; this is the "equiangular polygon theorem". Viviani's theorem holds for equiangular polygons: A rectangle (equiangular quadrilateral) with integer side lengths may be tiled
Rectification (geometry) 2r{p,q...}. For polyhedra, a birectification creates a dual polyhedron. Higher degree rectifications can be constructed for higher dimensional polytopes. In general an n-rectification truncates "n-faces" to points. If an n-polytope is (n-1)-rectified, its facets are reduced to points and the polytope becomes its dual. There are different equivalent notations for each degree of rectification. These tables show the names by dimension and the two type of facets for each. Facets are edges, represented as {2}. Facets are regular polygons. Facets are regular or rectified polyhedra. Facets are regular or rectified 4-polytopes. Rectification (geometry) In Euclidean geometry, rectification or complete-truncation is