A Theorem on the Dihedral Angles of a Tetrahedron

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Let ,
,
,
,
,
be the edges of a tetrahedron and let
,
,
,
,
,
be the corresponding dihedral angles. Define the function
on pairs of opposite edges and dihedral angles as
, where
is the dihedral angle at
and
is the dihedral angle at
.
Contributed by: Izidor Hafner (February 2017)
Open content licensed under CC BY-NC-SA
Snapshots
Details
The proof can be found in [1, p. 101, p. 113].
Reference
[1] V. V. Prasolov and I. F. Sharygin, Problems in Stereometry (in Russian), Moscow: Nauka, 1989.
Permanent Citation
"A Theorem on the Dihedral Angles of a Tetrahedron"
http://demonstrations.wolfram.com/ATheoremOnTheDihedralAnglesOfATetrahedron/
Wolfram Demonstrations Project
Published: February 8 2017