polygon with 15 sides

A pentadecagon or quindecagon or 15-gon is a shape with 15 sides and 15 corners.

Regular pentadecagon
A regular pentadecagon
TypeRegular polygon
Edges and vertices15
Schläfli symbol{15}
Coxeter diagramCDel node 1.pngCDel 15.pngCDel node.png
Symmetry groupDihedral (D15), order 2×15
Internal angle (degrees)156°
Dual polygonSelf
PropertiesConvex, cyclic, equilateral, isogonal, isotoxal

Regular pentadecagonEdit

All sides of a regular pentadecagon are the same length. Each corner is 156°. All corners added together equal 2340°.


The amount of space a regular pentadecagon takes up is


a is the length of one of its sides.


A regular triangle, decagon, and pentadecagon can completely fill a plane vertex.