The radius of a cylinder is increased by $20 \%$,keeping its height unchanged. What is the percentage increase in its volume?

The curved surface area of a hemisphere is $27.72 \text{ cm}^2$ and its volume is $19.404 \text{ cm}^3$. Find its radius in $\text{cm}$.

An iron cube of $10\, cm$ sides is hammered into a rectangular sheet of thickness $0.5\, cm$. If the sides of the sheet are in the ratio $1:5$, the sides (in $cm$) are:

$66 \text{ cm}^3$ of silver is drawn into a wire $1 \text{ mm}$ in diameter. The length of the wire in metres will be

$A$ cylindrical jar of diameter $24\, cm$ contains water to a height of $30\, cm$. $A$ spherical steel ball is dropped into the jar and the level of the water rises by $67.5\, mm$. The diameter of the ball is......$cm$.

The length of the diagonal of a cube is $6 \text{ cm}$. The volume of the cube (in $\text{cm}^3$) is (in $\sqrt{3}$)