# A heap of rice is in the form of a cone of diameter 9 m and height 3.5 m. Find the volume of the rice. How much canvas cloth is required to just cover the heap?

Given

Base Diameter of conical heap = 9 cm

Height, h of conical heap = 3.5 cm

Find out

We have to determine the the volume of the rice and canvas cloth is required to just cover the heap.

Solution

First will determine the slant height of the conical heap

$$\begin{array}{l}l=\sqrt{(r^{2}+h^{2})}\end{array}$$
$$\begin{array}{l}l=\sqrt{(4.5^{2}+3.5^{2})}\end{array}$$
$$\begin{array}{l}l=\sqrt{(20.25+12.25)}\end{array}$$
$$\begin{array}{l}l=\sqrt{32.5}\end{array}$$

=5.7 cm

Volume of cone = 1/3πr2h

Volume of rice = Volume of conical heap

Volume of rice = 1/3π(4.5)2(3.5)= 74.25cm3

Canvas requires to just cover heap = Curved surface area of conical heap

Curved surface area of a cone = πrl

Therefore, the canvas required = π(4.5)(5.7) = 80.61 cm2 [appx]

Therefore, the canvas required = 80.61 cm2 [appx]