Theorem 4.1.1. Law of Sines.
In triangle we have
which may also be written in the form
The first form is more convenient when we are trying to find an angle and the second form is more convenient when we are trying to find a side.
Case | Condition on Opposite Side | Number of Triangles | |
1 | acute | opposite side |
None |
2 | acute | opposite side = altitude | One (right triangle) |
3 | acute | altitude |
Two |
4 | acute | opposite side |
One |
5 | obtuse | opposite side |
None |
6 | obtuse | opposite side |
One |