If x is the distance from centre fo the circle, with radius 25cm, to its intersection point with the common chord, x²+24²=25² =>x=7cm.
Distance from this intersecting point to the centre of the other circle=39–7=32cm
Ratio of the sides of the right triangle thus formed is 24:32=3:4. Since 3:4:5 is the basic pythagorean triplet, the radius of the other circle=5*24/3=40cm.
Aliter: radius of the other circle=√32²+24²= 40cm.
