GCSE Maths: Circles Powerpoint (20 lessons)

Here is a collection of circles powerpoints, not just questions but examples and instruction. Includes answers. Covers what is pi, area and circumference, sectors, segments, perimeters, compound shapes, volume of cylinders, cones and spheres, equation of a circle, simultaneous equations, circle theories, pretty much all circle stuff i could think off. Includes a bit of rounding practise. Please let me know what you think or inbox me if you find a mistake, be nice, I'd love to make it better and make the next one better than this.