$A$ tank is in the form of a cylinder with radius $21\, cm$ closed at both the ends by hemispheres. If the total height of the tank is $62\, cm$, how many litres of water can it store? (in $liters$)

The radii of a frustum of a cone are $14 \,cm$ and $7 \,cm$. If its height is $24 \,cm$,find its curved surface area,total surface area,and volume.

$A$ solid metallic hemisphere of radius $8 \, cm$ is melted and recast into a right circular cone of base radius $6 \, cm$. Determine the height of the cone (in $cm$).

Total surface area of a cuboid measuring $15\,cm \times 12\,cm \times 10\,cm$ is $\ldots \ldots \ldots \,cm^{2}$.

The barrel of a fountain pen,cylindrical in shape,is $7 \, cm$ long and $5 \, mm$ in diameter. $A$ full barrel of ink in the pen is used up on writing $3300$ words on an average. How many words can be written in a bottle of ink containing one-fifth of a litre?

$CSA$ of a cylindrical tank with diameter $2.1 \, m$ and height $5 \, m$ is $\ldots \ldots \ldots \ldots \, m^2$.