Find the radius of a sphere whose surface area is $154 \, cm^2$. (in $, cm$)

What length of tarpaulin $3\, m$ wide will be required to make a conical tent of height $8\, m$ and base radius $6\, m$ (in $, m$)? Assume that the extra length of material that will be required for stitching margins and wastage in cutting is approximately $20\, cm$ (Use $\pi = 3.14$).

Find the capacity in litres of a conical vessel with radius $7 \, cm$ and slant height $25 \, cm$. (in $, l$)

Savitri had to make a model of a cylindrical kaleidoscope for her science project. She wanted to use chart paper to make the curved surface of the kaleidoscope (see figure). What would be the area of chart paper required by her,if she wanted to make a kaleidoscope of length $25\, cm$ with a $3.5\, cm$ radius (in $, cm^{2}$)? You may take $\pi=\frac{22}{7}$.

It is required to make a closed cylindrical tank of height $1 \,m$ and base diameter $140 \,cm$ from a metal sheet. How many square metres of the sheet are required for the same (in $,m^2$)? Assume $\pi = \frac{22}{7}$.

If the volume of a right circular cone of height $9 \, cm$ is $48 \pi \, cm^3$,find the diameter of its base. (in $, cm$)