# Compound of three triangular prisms

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Compound of three triangular prisms | |
---|---|

Rank | 3 |

Type | Uniform |

Elements | |

Components | 3 triangular prisms |

Faces | 9 squares, 6 triangles as 3 fissal enneagrams |

Edges | 9+18 |

Vertices | 18 |

Vertex figure | Isosceles triangle, edge lengths 1, √2, √2 |

Measures (edge length 1) | |

Circumradius | |

Volume | |

Dihedral angles | 4–3: 90° |

4–4: 60° | |

Height | 1 |

Central density | 3 |

Number of external pieces | 20 |

Level of complexity | 6 |

Related polytopes | |

Army | Semi-uniform Ep, edge lengths (base), 1 (sides) |

Regiment | * |

Dual | Compound of three triangular tegums |

Conjugate | Compound of three triangular prisms |

Abstract & topological properties | |

Flag count | 108 |

Orientable | Yes |

Properties | |

Symmetry | I_{2}(9)×A_{1}, order 36 |

Convex | No |

Nature | Tame |

The **fissal enneagrammic prism** or **compound of three triangular prisms** is a prismatic uniform polyhedron compound. It consists of 2 fissal enneagrams and 9 squares. Each vertex joins one fissal enneagram and two squares. As the name suggests, it is a prism based on a fissal enneagram.

Its quotientprismatic equivalent is the 9-3 step prismatic prism, which is five-dimensional.

## Vertex coordinates[edit | edit source]

Coordinates for the vertices of a fissal enneagrammic prism of edge length 1 centered at the origin are given by: