The parts of SSA may not determine a triangle.
For instance, if you are given an angle (A), the side adjacent to the angle (S1), and the side opposite to the angle (S2), S2 must be at least as large as S1·sin(A).
if A = 30°, S1 = 12, and S2 = 5, there won't be a triangle, S2 is too short!
S1·sin(A) = 12·sin(30) = 6 ---> means that there won't be a triangle because S2 is too short (it's only 5).
If S2 < S1·sin(A) ---> there won't be a triangle.
If S2 = S1·sin(A) ---> the triangle is a right triangle.
If S2 > S1·sin(A) and S2 < S1 ---> there will be two possible triangles.
If S2 > S1·sin(A) and S2 ≥ S1 ---> there will be one triangle.