The respective ratio of the curved surface area and total surface area of a cylinder is $4:5$. If the curved surface area of the cylinder is $1232 \, cm^2$,what is the height? (in $cm$)

$A$ large solid sphere is melted and moulded to form identical right circular cones with base radius and height same as the radius of the sphere. One of these cones is melted and moulded to form a smaller solid sphere. Then the ratio of the surface area of the smaller to the surface area of the larger sphere is

$A$ right circular cylindrical tunnel of diameter $5\, m$ and length $10\, m$ is to be constructed from a sheet of iron. The area of iron sheet required will be..........$\pi\, m^2$.

$A$ rectangular block of metal has dimensions $21\, cm$, $77\, cm$, and $24\, cm$. The block is melted into a sphere. The radius of the sphere is .......... $cm$. (Take $\pi = \frac{22}{7}$)

$A$ cone and a cylinder having the same area of the base have also the same area of curved surfaces. If the height of the cylinder is $2 \, m$,find the slant height of the cone (in $m$).

The volume of a conical tent is $1232 \, m^3$ and the area of its base is $154 \, m^2$. Find the length of the canvas required to build the tent,if the canvas is $2 \, m$ in width. (in $m$) (Take $\pi = \frac{22}{7}$)