Well-constrained

The smaller inner triangle can be determined since the length of two edges and the angle between them is given. The larger inner triangle can now be determined since two edge lengths are given and the third can be computed from the first triangle. Since this new triangle shares an edge with the first triangle, there are four possible positions for this triangle with respect to the first one. The outer triangle can then be fixed for each of these configurations because the lengths of two edges are given, and the angle between the edges can be computed from the second triangle. Notice that several constraints that are used to fix the configuration are not given explicitly but instead are determined implicitly from other constraints.