i think my question formation was wrong. i will ask it in different way. I have an arc . and the end points of the arc are say (x1,y1) and (x2,y2). i have the radius of the circle( R). Now i need to find out the center of the circle(X,Y). I need the equation of finding the center of circle using above information and the centre is not at origin. Thanking you in advance.