The Law of Cosines, also known as the Cosine Formula, is a mathematical theorem used to determine the relationship between the sides and angles of a triangle. It states that the square of a side of a triangle is equal to the sum of the squares of the other two sides minus twice the product of the other two sides and the cosine of the included angle. The formula can be written mathematically as: c² = a² + b² - 2ab cos(C), where c is the length of the side opposite to the angle C, and a and b are the lengths of the other two sides of the triangle.
