Circle Theorems: Unlocking the Secrets of Angles in Circles

Imagine a perfectly round clock face. The hands of the clock start at the centre and reach the edge. Now imagine drawing lines from two points on the edge of the clock to another point also on the edge. Do you think those angles are related in a neat, predictable way? Surprisingly, yes — and mathematicians discovered these relationships thousands of years ago. Before we dive in, check what you remember: What is the sum of angles on a straight line? What is the sum of angles in a triangle? Keep these facts handy — you will use them today.