Regular pentagon

Regular pentagons

A regular pentagon has Schläfli symbol {5} and interior angles of 108°. It also has five lines of reflectional symmetry, and rotational symmetry of order 5 (through 72°, 144°, 216° and 288°). The diagonals of a convex regular pentagon are in the golden ratio to its sides. Given its side length ${\displaystyle t,}$ its height ${\displaystyle H}$ (distance from one side to the opposite vertex), width ${\displaystyle W}$ (distance between two farthest separated points, which equals the diagonal length ${\displaystyle D}$) and circumradius ${\displaystyle R}$ are given by: