
A professional manufacturer of threedimensional measuring devices for the onmachine measurement and inmachine measurement 
I want to measure the radius r and the x and y coordinates of the center of the outer contour surface of the template processed as programmed.  
From A mathematical formula x² + y² + Ax + By + C = 0, substitute the values x and y at three arbitrary coordinates of the outer shape measured on the machining center to obtain A, B and C by threedimensional equations. From Pythagorean right triangle theorem (x  a) 2+ (y  b) 2 = r 2, we can find a = x coordinate, b = y coordinate and radiusr.
"Centering and Diameter Measurement (Machine Tool / Touch Probe)" is issued with the Internet free application. Download and automatically calculate when you input the coordinates of 3 points with the point finder. 

Products that are relevant to this question is as follows. It will jump to the corresponding page by clicking. [Point Finder Series] [Tool Setter Series] [Centering Gauge Swing Type] 