Coordinate geometry of a circle

At the end of this activity, students should be able to:
– place the circumference of the circle given by the equation (x – x0)2 + (y – y0)2 = r2 in the coordinate system
– place the disc (x – x0)2 + (y – y0)2 ? r2 or (x – x0)2 + (y – y0)2< r2 in the coordinate system
– represent the equation of the circle x2 + y2 – 2ax – 2by + c = 0 in the form (x – x0)2 + (y – y0)2= r2
– find the equation of a circle with three points given.