# Heptagonal tegum

The **heptagonal tegum**, also called a **heptagonal bipyramid**, is a tegum with a heptagon as the midsection, constructed as the dual of a heptagonal prism. It has 14 isosceles triangles as faces, with 2 order–7 and 7 order–4 vertices.

Heptagonal tegum | |
---|---|

Rank | 3 |

Type | Uniform dual |

Notation | |

Bowers style acronym | Het |

Coxeter diagram | m2m7o () |

Elements | |

Faces | 14 isosceles triangles |

Edges | 7+14 |

Vertices | 2+7 |

Vertex figure | 2 heptagons, 7 squares |

Measures (edge length 1) | |

Dihedral angle | |

Central density | 1 |

Number of external pieces | 14 |

Level of complexity | 3 |

Related polytopes | |

Army | Het |

Regiment | Het |

Dual | Heptagonal prism |

Conjugates | Heptagrammic tegum, Great heptagrammic tegum |

Abstract & topological properties | |

Flag count | 84 |

Euler characteristic | 2 |

Surface | Sphere |

Orientable | Yes |

Genus | 0 |

Properties | |

Symmetry | I_{2}(7)×A_{1}, order 28 |

Convex | Yes |

Nature | Tame |

In the variant obtained as the dual of a uniform heptagonal prism, the side edges are times the length of the edges of the base heptagon. Each face has apex angle and base angles . If the base heptagon has edge length 1, its height is .

## External links edit

- Wikipedia contributors. "Heptagonal bipyramid".
- McCooey, David. "Heptagonal Dipyramid"