The volume of the larger sphere of radius $R$ is twice the volume of smaller sphere of radius $r$. Find an equation connecting $r$ to $R$.

A piece of rope is wound around a cylindrical pipe $18$ times. If the diameter of the pipe is $600 \mathrm{mm}$, how long is the rope (in $\mathrm{mm}$)? (Use, $\mathrm{\pi }=3.14$)

A cylindrical rainwater tank is $1.5 \mathrm{m}$ tall with a diameter of $1.4 \mathrm{m}$. What is the maximum volume of rainwater (in ${\mathrm{cm}}^3$) it can hold?

The diagram shows the plan of a driveway to a house. Calculate the perimeter (in $\mathrm{m}$) of the driveway.

The diagram shows the plan of a driveway to a house. The driveway is made from concrete. The concrete is $15 \mathrm{cm}$ thick. Calculate the volume of concrete used for the driveway. Give your answer in cubic metres.

Find the area of trapezium (in ${\mathrm{cm}}^2$).

Calculate the volume of hemisphere (in ${\mathrm{cm}}^3$). Use, $\mathrm{\pi }=3.14$

Calculate the volume of hemisphere (in ${\mathrm{cm}}^3$) with radius $5 \mathrm{cm}$. Use, $\mathrm{\pi }=3.14$ (write answer to the nearest whole number)