$A$ hemisphere is made of lead. Its radius is $6 \, cm$. It is cast into a right circular cone of $75 \, cm$ height. The radius of the base of the cone is ......... $cm$.

The base of a $10\, cm$ high solid cylinder is a semi-circle of radius $7\, cm$. Its total surface area (in $cm^2$) is (Use $\pi = \frac{22}{7}$)

$A$ cylindrical bucket is $72\, cm$ high and $28\, cm$ in diameter and is full of water. This water is emptied into a rectangular tank whose length and breadth are $66\, cm$ and $28\, cm$,respectively. What will be the height of the water level in the tank? (in $cm$)

$A$ solid cone of height $36 \, cm$ and radius of base $9 \, cm$ is melted to form a solid cylinder of radius $9 \, cm$ and height $9 \, cm$. What percent of material is wasted in this process (in $\%$)?

The volume of the greatest sphere that can be cut off from a cylindrical log of wood of base radius $1 \, cm$ and height $5 \, cm$ is ....... $\pi \, cm^3$.

The perimeter of one face of a cube is $20\, cm$. Its volume is.........$cm^3$