How many cubic metres of masonry are there in a well $81 \mathrm{m}$ long, $4 \mathrm{m}$ high and $2 \mathrm{m}$ thick?

Find the height of a cuboid of volume $100 {\mathrm{cm}}^3$, whose length and breadth are $5 \mathrm{cm}$ and $4 \mathrm{cm}$ respectively.

A tank is $20 \mathrm{m}$  by $15 \mathrm{m}$  by $7 \mathrm{m}$ , Find its capacity of holding water if $1000 \mathrm{c}.\mathrm{c}. =1 \mathrm{litre}$.

A milk container is $8 \mathrm{cm}$ long and $50 \mathrm{cm}$ wide. What should be its height so that it can hold $4 \mathrm{litres}$ of milk?

Find the number of bricks required to build a wall $25 \mathrm{m}$ long,$35 \mathrm{cm}$ wide and $3.6 \mathrm{m}$ high if each brick (including mortar) occupies space$25 \mathrm{cm}\times 12.5 \mathrm{cm}\times 7 \mathrm{cm}$.

A cuboidal wooden block contain $36 {\mathrm{cm}}^3$ wood. If it be $4 \mathrm{cm}$ long and $3 \mathrm{cm}$ wide, find its height.

A rectangular water reservoir contains $72,000$ liters of water. Find the depth of water in the reservoir if its base measures $8 \mathrm{m}$ by $4.5 \mathrm{m}$.