If a circle passes through the point `(0,0),(a ,0)a n d(0, b)` , then find its center.

If a circle passes through the points (0,0),(a,0)and(0,b), then find the coordinates of its centre.

Find the equation of circle passing through the points : (0,0) ,(2,0) and (0,4) also, find its centre and radius.

If a circle passes through (0,0) and ( a,0) and (0,b) , then the coordinates of its centre are

Find the co-ordinates of the centre of the circle passing through the points (0,0)(-2,1) and (-3,2). Also find its radius.

Find the equation of the circle which passes through the points (7, 0) , (0, sqrt(7)) and has its centre on the x-axis.