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 $$Rs\ 12$$ per $$m^{2}$$.
It is given that
Radius of the cone $$=7\ m$$
Slant height of the cone $$=25\ m$$
We know that
Curved surface area of the cone $$=\pi rl$$
By substituting the values
Curved surface area of the cone $$=\dfrac{22}{7}\times 7\times 25$$
So we get
Curved surface area of the cone $$=550\ m^{2}$$
It is given that the cost of whitewashing $$=Rs\ 12\ per\ m^{2}$$
So the cost of whitewashing $$550\ m^{2}$$ area $$=Rs\ 12\times 550=Rs\ 6600$$
Therefore, the cost of whitewashing its curved surface area is $$Rs\ 6600$$