Law of Cosines
The Law of Cosines is a crucial formula used to find unknown sides or angles in any triangle. It states that for any triangle with sides a, b, and c opposite to angles A, B, and C respectively, the relationship is given by c² = a² + b² - 2ab * cos(C). This law is particularly useful when dealing with non-right triangles, as it allows for the calculation of angles and sides based on known values.