There are quite a few circle theorems to learn.

Why oh why? I hear you ask.

Circle theorems are a great way to investigate things using various properties and facts.

This is a great skill to have, be confident to play around and discover different facts not just in circles but in any form of mathematics.

Theorem - the angle at the centre is twice the angle at the circumference.

Example - The angle at the circumference is 38°. Applying this theorem 38 x 2 = 76°

So what are you waiting for?

Sometimes you have to recall other angle properties.

This is all part of the investigation of circles. Look out for these.