Question

Can someone explain the law of cosine to me please?

Answer 1

In any triangle, the square of any side is equal to the sum of the squares of the other two sides, diminished by twice the product of the other two sides and the cosine of the angle included between them:

a^2 = b^2 + c^2 - 2bc *cos α

b^2= a^2 + c^2 - 2ac*cos β

c^2 = a^2 + b^2 - 2ab cos γ