# Pentagonal magnabicupolic ring (EntityTopic, 17)

### From Hi.gher. Space

The **pentagonal magnabicupolic ring** is a CRF polychoron discovered by Quickfur. It is a member of the family of bicupolic rings, which contains eight other similar polychora. It is formed by attaching two pentagonal cupolae by their pentagonal faces, folding them into the fourth dimension with their decagonal ends connected by a decagonal prism, and then filling in the gaps with 5 triangular prisms and 5 square pyramids. For faces, it contains two decagons, one pentagon, 20 squares and 20 triangles.

It can also be constructed by the Stott expansion of the pentagonal prism pyramid.

## Dichoral angles

- Between pentagonal cupola and decagonal prism: 18° (exact)
- Between square pyramid and decagonal prism: atan(sqrt(5)-2) ≈ 13.28°
- Between triangular prism and decagonal prism: asin(sqrt((5-2*sqrt(5))/15)) ≈ 10.81°

## Cartesian coordinates

The coordinates of the pentagonal magnabicupolic ring are as follows:

# Decagonal prism <±2*phi, 0, ±1, 0> <±1, ±√(3+4*phi), ±1, 0> <±phi^2, ±√(2+phi), ±1, 0> # Pentagon <0, √((10+2*√5)/5), 0, √((5-2*√5)/5)> <±phi, √((5-√5)/10), 0, √((5-2*√5)/5)> <±1, -√((5+2*√5)/5), 0, √((5-2*√5)/5)>

## Equations

- Variables:

l⇒ edge length

- The hypervolumes of a pentagonal magnabicupolic ring are given by:

total edge length = 45l

total surface area =Unknown

surcell volume =Unknown

bulk =Unknown

- The realmic cross-sections (
*n*) of a pentagonal magnabicupolic ring are:

[!x,!y] ⇒Unknown

[!z] ⇒Unknown

[!w] ⇒Unknown

## Additional images

TODO: move this to a better place in the article. It's just here for now so it doesn't get lost.

## Software models

Notable Tetrashapes
| |

Regular:
| pyrochoron • aerochoron • geochoron • xylochoron • hydrochoron • cosmochoron |

Powertopes:
| triangular octagoltriate • square octagoltriate • hexagonal octagoltriate • octagonal octagoltriate |

Circular:
| glome • cubinder • duocylinder • spherinder • sphone • cylindrone • dicone • coninder |

Torii:
| tiger • torisphere • spheritorus • torinder • ditorus |