Find the curved surface area of a right circular cone whose slant height is $10\, cm$ and base radius is $7\, cm$. (in $, cm^{2}$)

The floor of a rectangular hall has a perimeter of $250\, m$. If the cost of painting the four walls at the rate of $10$ per $m^2$ is $Rs. 15000$,find the height of the hall. (in $, m$)

$A$ right circular cylinder just encloses a sphere of radius $r$ (see figure). Find:
$(i)$ Surface area of the sphere,
$(ii)$ Curved surface area of the cylinder,
$(iii)$ Ratio of the areas obtained in $(i)$ and $(ii)$.

Find the volume of a sphere of radius $11.2 \, cm$. (in $, cm^3$)

The diameter of a roller is $84\, cm$ and its length is $120\, cm$. It takes $500$ complete revolutions to move once over to level a playground. Find the area of the playground in $m^2$. $\left[\text{Assume } \pi = \frac{22}{7}\right]$ (in $, m^2$)

$A$ wall of length $10\, m$ was to be built across an open ground. The height of the wall is $4\, m$ and thickness of the wall is $24\, cm$. If this wall is to be built up with bricks whose dimensions are $24\, cm \times 12\, cm \times 8\, cm$,how many bricks would be required?