The number of balls, each of radius 1 cm can be made from a solid sphere of lead of radius 6 cm is

Radius of sphere($r$)=6 cm

Radius of ball($r_1$)=1 cm

No. of  balls =$\frac{\mathrm{volume} \mathrm{of} \mathrm{sphere}}{\mathrm{volume} \mathrm{of} \mathrm{ball}}$

$=\frac{{\displaystyle \frac{4}{3}}{\mathrm{\pi r}}^3}{{\displaystyle \frac{4}{3}}{\mathrm{\pi r}}_1^3}$

$=\frac{6\times 6\times 6}{1\times 1\times 1}$

$=216$