Dodecagon
The constructible regular 12-sided Polygon with Schläfli Symbol 
. TheInradius 
, Circumradius 
, and Area 
can be computed directly from the formulas for a generalregular Polygon with side length 
and 
sides,
 |  |  | (1) |
 | |  | (2) |
 | |  | (3) |
A Plane Perpendicular to a 
axis of a Dodecahedron or Icosahedron cuts the solid in a regularDecagonal Cross-Section (Holden 1991, pp. 24-25).
The Greek, Latin, and Maltese Crosses are all irregular dodecagons.
References
Holden, A. Shapes, Space, and Symmetry. New York: Dover, 1991.
- Primitive Sequence
- Primorial
- Prince Rupert's Cube
- Principal
- Principal Curvatures
- Principal Curve
- Principal Direction
- Principal Ideal
- Principal Normal Vector
- Principal Quintic Form
- Principal Radius of Curvature
- Principal Value
- Principal Vector
- Principal Vertex
- Principle
- Pringsheim's Theorem
- Printer's Errors
- Prior Distribution
- Prism
- Prismatic Ring
- Prismatoid
- Prismoid
- Prisoner's Dilemma
- Prizes
- Probability