What is the name of the solid created by joining two tetrahedra face-to-face?
By Emma Martinez •
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When I connect the bases of two pyramids, I will receive an octahedron. I have a question about an analogical situation with two tetrahedra. What is the name of a geometrical figure, which is a combination of two tetrahedra?
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$\begingroup$It's a triangular dipyramid, which is one of the $92$ Johnson solids (solids all of whose faces are regular but where the vertices do not all look the same).
$\endgroup$ $\begingroup$When joining two regular tetrahedra, the result is one of the Johnson solids, the triangular bipyramid.
Two general tetrahedra joined face-to-face can also be called triangular bipyramids, but these joins are not Johnson solids.
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