Pythagoras’ theorem ... right-angled triangle, which is always opposite the right angle. When labelling a length as the hypotenuse, it can be shortened to 𝒉. is equal to the sum of the ...

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.