To apply the Law of Cosines for finding the length of a side in a triangle, you need to know:
- The lengths of the other two sides of the triangle.
- The measure of the angle between those two sides.
In mathematical terms, if you wish to find the length of side c in triangle ABC, where a and b are the lengths of the other two sides and C is the angle opposite side c, the formula is:
c² = a² + b² – 2ab * cos(C)
This formula allows you to calculate the unknown side length by substituting the known values for sides a, b, and the angle C. Once you perform the calculations, you can find the length of side c.
Remember that this law is particularly useful for triangles that are not right-angled because it incorporates both side lengths and the angle, which provides the flexibility to solve a wider array of triangle problems.