Question

A bucket open at the top, and made up of a metal sheet is in the form of a frustum of a cone. The depth of the bucket is $24cm$ and the diameters of its upper and lower circular ends are $30cm$ and $10cm$ respectively. Find the cost of metal sheet used in it at the rate of Rs. $10$ per $100{cm}^2$. (Use $\pi =3.14$)

Answer 1

Area of sheet required $=\pi (R_1+R_2)\sqrt{{(R_1-R_2)}^2+h^2}+\pi R_2^2$

$\Rightarrow 3.14[(15+5)\sqrt{{(15-5)}^2+242}+5^2]=1711.3{cm}^2$

Cost of sheet $=Rs.\frac{(1711.3\times 10)}{100}=Rs.171.13$