Surface area of a cuboid = $\ldots \ldots \ldots$

Curved surface area of a hemisphere $= \ldots \ldots \ldots$

Two cubes each of $8 \, cm$ edge are joined end to end. Find the total surface area of the cuboid so formed (in $cm^{2}$).

$A$ storage tank is in the form of a cube. When it is full of water, the volume of water is $15.625 \, m^3$. If the present depth of water is $1.3 \, m$, find the volume of water already used from the tank (in $m^3$).

The radius of a cylinder is $10\, cm$ and its curved surface area is $440\, cm^{2}$. Then its height is $\ldots \ldots \ldots$

The length,breadth,and height of a hall are $7\, m$,$5\, m$,and $4\, m$ respectively. It has two doors measuring $3\, m \times 2\, m$ each and four windows measuring $2\, m \times 1\, m$ each. Find the cost of whitewashing all the four walls and the ceiling of the hall at the rate of ₹$200$ per $m^2$.