Math Central on Instagram: "The cosine law is a way to find a missing side or angle in any triangle. It says that if you know two sides and the angle between them, you can work out the third side, or if you know all three sides, you can find an angle. It works by linking the lengths of the sides to the cosine of an angle, which measures how “open” the angle is. This makes it a more general version of the Pythagorean theorem that works for all triangles, not just right-angled ones. #math #learnin