Find the total surface area of a hemisphere of radius $42 \, cm$. (in $cm^2$)

Find the lateral surface area of a cube with an edge length of $15 \, cm.$ (in $cm^{2}$)

Find the total surface area of a cylinder with diameter $28 \text{ cm}$ and height $50 \text{ cm}$. (in $\text{cm}^2$)

$A$ right circular cylinder just encloses a sphere of radius $r$ (see figure). Find:
$(i)$ Surface area of the sphere,
$(ii)$ Curved surface area of the cylinder,
$(iii)$ Ratio of the areas obtained in $(i)$ and $(ii)$.

In the Indus Valley Civilisation (about $3000 \, BC$),the bricks used had the ratio of $\ldots \ldots$ for length,breadth,and height,respectively.

$A$ village,having a population of $4000$,requires $150$ litres of water per head per day. It has a tank measuring $20 \,m \times 15 \,m \times 6 \,m$. For how many days will the water of this tank last?