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Goddard-Henning Enneahedron


GoddardHenningEnneahedron

The Goddard-Henning enneahedron, a term coined here, is the canonical polyhedron obtained from the Goddard-Henning graph. It has 9 vertices, 16 edges (consisting of 3 distinct edge lengths), and 9 faces (consisting of 3 distinct face types).

GoddardHenningEnneahedronSolidAndDual

It is a self-dual polyhedron.

GoddardHenningEnneahedronFaces

In particular, the bottom face is a square, the four faces sharing an edge with the bottom are isosceles triangles, and the remaining four faces that meet at the apex are kites. The face angles as shown are

theta_1=cos^(-1)(2/3)
(1)
theta_2=sec^(-1)(4)
(2)
theta_3=cos^(-1)((3-5sqrt(3))/(12))
(3)
phi_1=cos^(-1)((1+sqrt(3))/4)
(4)
phi_2=cos^(-1)((2-sqrt(3))/4).
(5)

For the polyhedron with unit midradius, the side lengths are

a=4sqrt(2/3-1/(sqrt(3)))
(6)
b=2sqrt(2/3)
(7)
c=2sqrt(6-3sqrt(3))
(8)

and the generalized diameter, surface area, and volume are

d=2sqrt(5/3)
(9)
S=8/3(1+sqrt(75+38sqrt(3)+2sqrt(30(54-31sqrt(3)))))
(10)
V=(16)/(27)(5sqrt(3)-3).
(11)
GoddardHenningEnneahedronNet

A net for the polyhedron is illustrated above.


See also

Enneahedron, Goddard-Henning Graph

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Cite this as:

Weisstein, Eric W. "Goddard-Henning Enneahedron." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Goddard-HenningEnneahedron.html

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