An understanding of how to use Pythagoras’ theorem to find missing sides in a right-angled triangle is essential for applying the theorem in different contexts. (3,1) is the coordinate that is 3 ...

In this triangle \(a^2 = b^2 + c^2\) and angle \(A\) is a right angle. Pythagoras' theorem only works for right-angled triangles, so you can use it to test whether a triangle has a right angle or not.