This calculator will work out the radius and centre of a circle which intersects three given points.
It sometimes happens that you need 3 points to sit on a circle. This calculator allows you to work back from these fixed points and find the centre point and radius of the circle which passes through them.
Imagine the three points are on an X/Y matrix as shown below:-
Enter the X/Y coordinates of the three points (10,10), (29.31,70) & (63.05,100) into the boxes below and it will calculate the radius and the coordinates of the centre for you. It does not matter what units you choose as long as you are consistent.