Triskaidecagon

Triskaidecagon

Regular triskaidecagon

Edges and vertices 13

Schläfli symbol {13}

Coxeter–Dynkin diagram

Symmetry group Dihedral (D₁₃)

Area
(with t=edge length) $\frac{13}{4}t^2 \cot \frac{\pi}{13}$
$\simeq 13.1858\,t^2$

Internal angle
(degrees) 180*(11/13) degrees
$\simeq 152.308$

In geometry, a triskaidecagon (or tridecagon) is a polygon with 13 sides and angles.

The measure of each internal angle of a regular triskaidecagon is approximately 152.308 degrees, and the area with side length a is given by

$A = \frac{13}{4}a^2 \cot \frac{\pi}{13} \simeq 13.1858\,a^2.$

A regular triskaidecagon is not constructible with compass and straightedge. However, it is constructible using a Neusis construction.

Related polygons

A triskaidecagram is a 13-sided star polygon. There are 5 regular forms given by Schläfli symbols: {13/2}, {13/3}, {13/4}, {13/5}, {13/6}.

v • d • e Polygons

Listed by number of sides

1-10 sides	Henagon (Monogon) · Digon · Triangle (Trigon) · Quadrilateral (Tetragon) · Pentagon · Hexagon · Heptagon · Octagon · Nonagon (Enneagon) · Decagon

11-20 sides	Hendecagon · Dodecagon · Triskaidecagon · Tetradecagon · Pentadecagon · Hexadecagon · Heptadecagon · Octadecagon · Nonadecagon (Enneadecagon) · Icosagon

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