Circle theorems are properties that are true for all circles, regardless of their size. There are six theorems to learn and recognise. Questions can have a combination of theorems. It is important to ...

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.