The slant height and base diameter of a conical tomb are $25 \, m$ and $14 \, m$ respectively. Find the cost of white-washing its curved surface at the rate of $Rs. 210$ per $100 \, m^2$.

If the total surface area of a cone is $3696 \, cm^{2}$ and the curved surface area of a cone is $2310 \, cm^{2}$,find the ratio of the radius to the slant height.

Curved surface area of a cone $= \dots$

$A$ bus stop is barricaded from the remaining part of the road by using $50$ hollow cones made of recycled cardboard. Each cone has a base diameter of $40 \, cm$ and height $1 \, m$. If the outer side of each of the cones is to be painted and the cost of painting is $Rs. 12$ per $m^2$,what will be the cost of painting all these cones? (Use $\pi = 3.14$ and take $\sqrt{1.04} = 1.02$)

Find the curved surface area and the total surface area of a cone with radius $3.5 \, cm$ and height $12 \, cm$.

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