The Law of Sines is the relationship between the sides and angles of non-right (oblique) triangles . Simply, it states that the ratio of the length of a side of a triangle to the sine of the angle opposite that side is the same for all sides and angles in a given triangle. The formula for it is A=b•sin a/sin b.
You can transform the law of sines formulas to solve some problems of triangulation (solving a triangle). You can use them to find:
The remaining sides of a triangle, knowing two angles and one side. The third side of a triangle, knowing two sides and one of the non-enclosed angles. In some cases (ambiguous cases) there may be two solutions to the same triangle. If the following conditions are fulfilled, your triangle may be an ambiguous case: You only know the angle α and sides a and c; Angle α is acute (α < 90°); a is shorter than c (a < c); a is longer than the altitude h from angle β, where h = c * sin(α) (a > c * sin(α)).