Question 935228
R, radius of whole ball
r, radius of inner ball (just the lead)
Using x as radius, {{{(4/3)pi*x^3}}} is volume formula for sphere.


THINK:  volume of whole ball minus volume of inner ball is the volume of the gold shell.  Volume of gold shell equals volume of inner ball.


THAT is help, and I leave the rest of the solution undone but for you to do.  Watch carefully that DIAMETER is 2*radius.