Watch more videos like this one: https://www.revisionboost.com/

This video covers the nine circle theorems that you need to understand before sitting your maths GCSE exams, along with some example question walkthroughs. Here is a brief summary of the nine theorems:

1.) A tangent and a radius must always meet at 90 degrees
2.) Two radii form an isosceles triangle
3.) The perpendicular bisector of a chord passes through the centre of a circle
4.) The angle at the centre of a circle is twice the angle at the circumference
5.) The angle in a semicircle is 90 degrees
6.) Angles in the same segment are equal
7.) Opposite angles in a cyclic quadrilateral add to give 180 degrees
8.) Tangents from the same point are the same length
9.) The angle between a tangent and a chord is equal to the tangent in the opposite segment (the alternate segment theorem.)

We hope this helps!