Volume between cylinder and sphere =
pi * r^2 * h - (4/3)pi * radius^3 =
pi [ 3^2 * 6 - (4/3)*3^3 ] =
pi [ 54 - 36 ] =
18 pi cm^3
Surface area of sphere = 4 pi* radius^2 = 4 * pi * 3^2 = 36 pi cm^2
Surface area of cone = pi * radius * l = pi * 3x * l = 3pi * l
So
36 pi = 3x * pi * l
l = 36pi / [ 3x * pi ] = 12 / x cm