This page will demonstrate all the circle theorems that you need to know.
They are interactive, so you can move the points around and see how the angles change. This is a great way to help you visualise the theorems.
Before we begin, you should watch an introductory video to circle theorems.
These interactive demonstrations all you need to see the circle theorems relations. Try dragging the dots around the screen to manipulate each circle graphic. The angle relationships should become clear!
Thanks to Desmos for their awesome free software.
IGCSE Intersecting Chords Theorems
Here you can drag the points around and see in real time how the lengths of the chords are related.
Watch all of our Circle Videos in this playlist.
Ready for practice? The below buttons are direct links to exam style questions.
Addvance Maths 