To help with some revision my Year 12s were doing I have today just finished some summary notes and exercises (to be fair there are more questions than notes) on Circle Geometry.
They start from the basics as shown below:
and then progress to the more difficult problem solving questions, such as determining the equation of a circle that passes through 3 points.
Feel free to use them and download from below:
NB: This is my second post for #MathsWeekEngland. Check out their website here.