Question

A heap of wheat is in the form of a cone of diameter 9 m and height 3.5 m.Find its volume.How much canvas cloth is required to just cover the heap?$(Use\pi =3.14)$

Answer 1

Diameter of conical heap of wheat=9 m

$\therefore Radius\left(r\right)=\frac{9}{2}mandheight\left(h\right)=3.5m=\frac{7}{2}mVolume=\frac{1}{3}\pi r^{2}h=\frac{1}{3}\times 3.14\times \frac{9}{2}\times \frac{9}{2}\times \frac{7}{2}{m}^3=74.18m^{3}Curvedsurfacearea=\pi rll=\sqrt{r^2+h^2}=\sqrt{{\left(\frac{9}{2}\right)}^2+{\left(\frac{7}{2}\right)}^2}=\sqrt{\frac{81}{4}+\frac{49}{4}}=\sqrt{\frac{130}{4}}=\frac{\sqrt{130}}{2}\therefore Surfacearea=3.14\times \frac{\sqrt{130}}{2}\times \frac{9}{2}c{m}^2=3.14\times \frac{11.4}{2}\times \frac{9}{2}c{m}^2=80.54c{m}^2$