$A$ room without a ceiling is $12 \, m$ long,$4 \, m$ wide,and $3 \, m$ high. Find the length of the longest rod that can be placed in that room. (in $m$)

The total surface area of a cone whose radius is $\frac{r}{2}$ and slant height is $2l$ is

Write True or False and justify your answer in each of the following:
The volume of the largest right circular cone that can be fitted in a cube whose edge is $2r$ is equal to the volume of a hemisphere of radius $r$.

The dimensions of each iron hollow box are $30 \, cm \times 15 \, cm \times 10 \, cm$. What is the volume of a carton containing $60$ such boxes? (in $m^3$)

Find the surface area of a sphere of radius $30 \, cm$ $(\pi = 3.14)$ (in $cm^2$).

The dimensions of a cuboidal box are in the ratio $6: 4: 3$. The difference between the cost of covering it with white paper at the rate of $₹ 2.00$ per $m^2$ and with coloured paper at the rate of $₹ 2.50$ per $m^2$ is $₹ 1350$. Find the dimensions of the box.