Question

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

Answer 1

$l=25m,d=14m\Rightarrow r=\frac{14}{2}=7m$
CSA of a cone$=\pi rl=\frac{22}{7}\times 7m\times 25m$
$\therefore$ CSA of conical tomb$=550m^2$
Cost of white washing $100m^2=Rs.210$
$\therefore$ Cost of white washing$550m^2=\frac{Rs.210}{100m^2}\times 550m^2=Rs.1155$.