The dihedral angle is the angle 
between two planes. The dihedral angle between the planes
which have normal vectors 
and 
is simply given via the dot product of the normals,
The dihedral angle is therefore trivial to compute via equation (3) if the two planes are specified in Hessian normal form
 | (5) |
for planes 
(Gellert et al. 1989, p. 541).
The dihedral angle between planes in a general tetrahedron is closely connected with the face areas via a generalization of the law of cosines.
See also
Angle,
Contact Angle,
Hessian Normal Form,
Line-Line Angle,
Plane,
Plane-Plane Intersection,
Tetrahedron,
Trihedron,
Vertex Angle Explore with Wolfram|Alpha
References
Gellert, W.; Gottwald, S.; Hellwich, M.; Kästner, H.; and Künstner, H. (Eds.). VNR Concise Encyclopedia of Mathematics, 2nd ed. New York: Van Nostrand Reinhold, 1989.Kern, W. F. and Bland, J. R. Solid Mensuration with Proofs, 2nd ed. New York: Wiley, p. 15, 1948.Referenced on Wolfram|Alpha
Dihedral Angle Cite this as:
Weisstein, Eric W. "Dihedral Angle." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/DihedralAngle.html
Subject classifications
