Draw and label a standard Oblique Triangle, as we’ve done in our previous lessons.
Determine the given congruence, either SAS or SSS, and pick the equation that helps you solve for either a missing side or angle.
Plug into your chosen equation and solve.
The "Law of Cosines" can be used to calculate one side of a triangle when the angle opposite and the other two sides are known. The "Law of Cosines" can be expressed as c2 = a2 + b2 - 2 a b cos C (1)
The cosine rule is an extension of this mathematic principal that makes it effective for non-right triangles and states that in regard to a certain angle, the square of the side of the triangle opposite that angle is equal to the squares of the other two sides added together, minus two times both..
