Triacontagon

Regular triacontagon

A regular triacontagon
Type general type of this shape
Edges and vertices 30
Schläfli symbol {30}
t{15}
Coxeter–Dynkin diagrams
Symmetry group Dihedral (D30)
Internal angle (degrees) 168°
Properties convex, cyclic, equilateral, isogonal, isotoxal

In geometry, an triacontagon is a thirty-sided polygon. The sum of any triacontagon's interior angles is 5040 degrees.

One interior angle in a regular triacontagon is 168° meaning that one exterior angle would be 12°

The regular triacontagon is a constructible polygon, by an edge-bisection of a regular pentadecagon, and can be seen as a truncated pentadecagon.

Area

The area of a regular triacontangon is (with t = edge length)

A = \frac{15}{2} t^2 \cot \frac{\pi}{30}

Petrie polygons

The regular triacontagon is the Petrie polygon for a number of higher dimensional polytopes with E8 symmetry, shown in orthogonal projections in the E8 Coxeter plane:


(421)

t1(421)

t2(421)

(241)

t1(241)

It is also the Petrie polygon for some higher dimensional polytopes with H4 symmetry, shown in orthogonal projections in the H4 Coxeter plane:


120-cell

Rectified 120-cell

Rectified 600-cell

600-cell

References