Truncated triakis tetrahedron

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Truncated triakis tetrahedron
Truncated triakis tetrahedron.png
Type Near-miss Johnson solid
Faces 4 hexagons
12 irregular pentagons
Edges 42
Vertices 28
Vertex configuration 4 (5.5.5)
24 (5.5.6)
Conway notation t6kT = dk6tT
Symmetry group Td
Dual polyhedron Hexakis truncated tetrahedron
Properties convex
Net
Conway dk6tT net.png
Truncated triakis tetrahedron.gif

In geometry, the truncated triakis tetrahedron, or more precisely an order-6 truncated triakis tetrahedron, is a convex polyhedron with 16 faces: 4 sets of 3 pentagons arranged in a tetrahedral arrangement, with 4 hexagons in the gaps.

Contents

Construction

It is constructed from a triakis tetrahedron by truncating the order-6 vertices. This creates 4 regular hexagon faces, and leaves 12 mirror-symmetric pentagons.

Triakis tetrahedron Triakistetrahedron.jpg
Triakis tetrahedron

A topologically similar equilateral polyhedron can be constructed by using 12 regular pentagons with 4 equilateral but nonplanar hexagons, each vertex with internal angles alternating between 108 and 132 degrees.

Topologically, as a near-miss Johnson solid, the four hexagons corresponding to the face planes of a tetrahedron are triambi, with equal edges but alternating angles, while the pentagons only have reflection symmetry.

Full truncation

If all of a triakis tetrahedron's vertices, of both kinds, are truncated, the resulting solid is an irregular icosahedron, whose dual is a trihexakis truncated tetrahedron.

Truncation of only the 3-valence vertices yields the order-3 truncated triakis tetrahedron, which looks like a tetrahedron with each face raised by a low triangular frustum. The dual to that truncation will be the triakis truncated tetrahedron.

StellaTruncTriakisTetra.png

Hexakis truncated tetrahedron

Hexakis truncated tetrahedron rotating Hexakis truncated tetrahedron.gif
Hexakis truncated tetrahedron rotating

The dual of the order-6 Truncated triakis tetrahedron is called a hexakis truncated tetrahedron. It is constructed by a truncated tetrahedron with hexagonal pyramids augmented. If all of the triangles are made regular, the polyhedron becomes a failed Johnson solid, with coplanar triangles in a truncated tetrahedron volume.

Polyhedron truncated 4a max.png
truncated tetrahedron
Conway k6tT.png
Hexakis truncated tetrahedron
Conway k6tT net.png
Net

See also


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