Question 760267
Volume(V) of a ball is 4/3 * pi * radius^3
V of new ball = 4/3 *pi *5^3 + 4/3 *pi * 4^3 +4/3 *pi *3^3 (radius is 1/2 diameter)
factor 4/3 and pi from equation
V of new ball = 4/3*pi*(5^3 +4^3 + 3^3)
V of new ball = 4/3*pi*216 = 905.14
notice that 6^3 = 216, so the diameter of the new ball is 6*2 = 12cm