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