$A$ shot-put is a metallic sphere of radius $4.9 \, cm$. If the density of the metal is $7.8 \, g/cm^3$,find the mass of the shot-put. (in $, kg$)

$A$ dome of a building is in the form of a hemisphere. From inside,it was white-washed at the cost of $Rs. 4989.60$. If the cost of white-washing is $Rs. 20$ per square metre,find the inside surface area of the dome. (in $, m^2$)

Twenty-seven solid iron spheres,each of radius $r$ and surface area $S$,are melted to form a single sphere with surface area $S'$. Find the ratio of $S$ to $S'$.

$A$ godown measures $60 \,m \times 25 \,m \times 15 \,m$. Find the maximum number of wooden crates each measuring $1.5 \,m \times 1.25 \,m \times 0.5 \,m$ that can be stored in the godown.

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

$A$ right triangle $ABC$ with sides $5 \, cm, 12 \, cm$ and $13 \, cm$ is revolved about the side $12 \, cm$. Find the volume of the solid so obtained. Also,find the volume of the solid obtained when the same triangle is revolved about the side $5 \, cm$. Finally,find the ratio of the volumes of the two solids.