As 14 = 2 × 7, a regular tetradecagon cannot be constructed using a compass and straightedge. However, it is constructible using neusis with use of the angle trisector, or with a marked ruler, as shown in the following two examples. , based on the angle trisection by means of the Tomahawk., pause at the end of 25 s The animation below gives an approximation of about 0.05° on the center angle: Construction of an approximated regular tetradecagon Another possible animation of an approximate construction, also possible with using straightedge and compass. Based on the unit circle r = 1
Constructed side length of the tetradecagon in GeoGebra
The regular tetradecagon has Dih14 symmetry, order 28. There are 3 subgroup dihedral symmetries: Dih7, Dih2, and Dih1, and 4 cyclic group symmetries: Z14, Z7, Z2, and Z1. These 8 symmetries can be seen in 10 distinct symmetries on the tetradecagon, a larger number because the lines of reflections can either pass through vertices or edges. John Conway labels these by a letter and group order. Full symmetry of the regular form is r28 and no symmetry is labeled a1. The dihedral symmetries are divided depending on whether they pass through vertices or edges, and i when reflection lines path through both edges and vertices. Cyclic symmetries in the middle column are labeled as g for their central gyration orders. Each subgroup symmetry allows one or more degrees of freedom for irregular forms. Only the g14 subgroup has no degrees of freedom but can seen as directed edges. The highest symmetry irregular tetradecagons are d14, an isogonal tetradecagon constructed by seven mirrors which can alternate long and short edges, and p14, an isotoxal tetradecagon, constructed with equal edge lengths, but vertices alternating two different internal angles. These two forms are duals of each other and have half the symmetry order of the regular tetradecagon.
Dissection
states that every zonogon can be dissected into m/2 parallelograms. In particular this is true for regular polygons with evenly many sides, in which case the parallelograms are all rhombi. For the regular tetradecagon, m=7, and it can be divided into 21: 3 sets of 7 rhombs. This decomposition is based on a Petrie polygon projection of a 7-cube, with 21 of 672 faces. The list defines the number of solutions as 24698, including up to 14-fold rotations and chiral forms in reflection.
Numismatic use
The regular tetradecagon is used as the shape of some commemorative gold and silver Malaysian coins, the number of sides representing the 14 states of the Malaysian Federation.
Related figures
A tetradecagram is a 14-sided star polygon, represented by symbol. There are two regular star polygons: and, using the same vertices, but connecting every third or fifth points. There are also three compounds: is reduced to 2 as two heptagons, while and are reduced to 2 and 2 as two different heptagrams, and finally is reduced to seven digons. A notable application of a fourteen-pointed star is in the flag of Malaysia, which incorporates a yellow tetradecagram in the top-right corner, representing the unity of the thirteen states with the federal government. Deeper truncations of the regular heptagon and heptagrams can produce isogonal intermediate tetradecagram forms with equally spaced vertices and two edge lengths. Other truncations can form double covering polygons 2, namely: t2, t2, and t2.
Petrie polygons
tetradecagons exist as Petrie polygon for many higher-dimensional polytopes, shown in these skew orthogonal projections, including:
