Regular polyhedron a hemisphere, and vertices around a great circle. It is "regular" if the vertices are equally spaced. The hosohedron {2,"n"} is dual to the dihedron {"n",2}. Note that when "n" = 2, we obtain the polyhedron {2,2}, which is both a hosohedron and a dihedron. All of these have Euler characteristic 2. Regular polyhedron A regular polyhedron is a polyhedron whose symmetry group acts transitively on its flags. A regular polyhedron is highly symmetrical, being all of edge-transitive, vertex-transitive and face-transitive. In classical contexts, many different equivalent definitions are used; a common one is that faces are congruent regular polygons
Regular polygon edges and faces in orthogonal projections "m"-cubes. In particular this is true for regular polygons with evenly many sides, in which case the parallelograms are all rhombi. The list gives the number of solutions for smaller polygons. The area "A" of a convex regular "n"-sided polygon having side "s", circumradius "R", apothem "a", and perimeter "p" is given by For regular polygons with side "s" = 1, circumradius "R" = 1, or apothem "a" = 1, this produces the following table: (Note that since formula_11 as formula_12, the area when formula_13 is tending to formula_14 as formula_15 grows large.) Of