Equation of a Circle

Change the measure of the raidus. Start by dragging point P anywhere. What do you observe?
Next , maintain the measure of the radius, change the coordinates of the center.[br]1. Click the blue segment , radius, and move the circle horizontaly.[br] What do you observe ?[br]2. Move the circle vertically. What do you observe? [br]3. Move the circle diagonally. What do you observe?

Information: Equation of a Circle