1. The problem statement, all variables and given/known data I am trying to find the face angles on a tetrahedron. I have only the base edge lengths, the angles connected the base edges and an (approximate) height of the top/non-base vertex. I might be able to extrapolate other information from images of the base of the tetrahedron, but I'm not quite sure what would be useful. For the curious: I'm attempting to determine aerial position from images using known ground landmarks (Fischler-Bolles). 2/3. Relevant equations and The attempt at a solution I'm really looking for an Introduction to the Geometry of a Non-Regular Tetrahedron. I've checked with math libraries, been steered towards Topology, but that's all been mostly not relevant. Everything I've been able to find has been for regular tetrahedrons. Mine is not regular. Pointers to places on the web which would walk me through deriving angles or edge lengths on a non-regular tetrahedron would be VERY much appreciated. Many Thanks.