$A$ ball of lead,$4\, cm$ in diameter,is covered with gold. If the volume of the gold and lead are equal,then the thickness of gold is approximately (in $cm$).
$[$ Given $\sqrt[3]{2} = 1.259 ]$

If the surface area of a sphere is $346.5 \, cm^{2},$ then its radius is.......$cm$
$\left[\text{taking } \pi = \frac{22}{7}\right]$

How many coins,$2 \, mm$ thick and $1.5 \, cm$ in diameter,should be melted in order to form a right circular cylinder with base diameter $6 \, cm$ and height $8 \, cm$?

The outer dimensions of a closed wooden box of $1 \text{ cm}$ thickness are $12 \text{ cm} \times 10 \text{ cm} \times 8 \text{ cm}$. Find the cost of the wood required to make the box if $1 \text{ cm}^3$ of wood costs $₹ 3.00$.

The length of canvas $75 \, cm$ wide required to build a conical tent of height $14 \, m$ and the floor area $346.5 \, m^{2}$ is.........$m$

$A$ 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......$cm$.