1. The problem statement, all variables and given/known data Find the equation of the circle whose centre lies on the x axis and which passes through points A (6,0) and B (0,10). 2. Relevant equations 3. The attempt at a solution I drew a diagram of the circle and determined that the line AB has gradient 5/3. Its perpendicular bisector should pass through the centre of the circle. This perpendicular line has a gradient of -3/5 and, I think, an equation of 3x+5y-34=0. The centre lies on the x-axis, so the y-coordinate at the centre must be 0. Hence I can use the equation of the perpendicular line to solve for x at point (x,0). I get 34/4 for x here, giving a centre at (34/3 ,0). I am not sure where to go now, or if the above is even correct. Any help greatly appreciated.