Regular polygon is denoted by its Schläfli symbol {"n"}. For "n" < 3, we have two degenerate cases: In certain contexts all the polygons considered will be regular. In such circumstances it is customary to drop the prefix regular. For instance, all the faces of uniform polyhedra must be regular and the faces will be described simply as triangle, square, pentagon, etc. For a regular convex "n"-gon, each interior angle has a measure of: and each exterior angle (i.e., supplementary to the interior angle) has a measure of formula_5 degrees, with the sum of the exterior angles equal to 360 degrees or
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