Open University (OU) Visualizing circles, part of the Exploring Mathematics course(course code MST121). (Math Mathematics Maths)
Course websites
http://www.open.ac.uk/courses/tasters/mst121/
http://www3.open.ac.uk/courses/bin/p12.dll?C01MST121
A Circle can be thought of as:
1. Points equidistant from a fixed point
2. Three points fix a circle
3. Angles subtended by a fixed chord
4. Horizontal and vertical components
