Question

The radii of the circular bases of a frustum of a right circular cone are $12cm$ and $3cm$ and the height is $12cm$. Find the total surface area and the volume of the frustum.

Answer 1

Surface area of bucket$=$ Surface of frustum

$R=12cm,r=3cm,h=12cm$

$A=\pi (R+r)\sqrt{(R-r{)}^2+h^2}$

$A=\pi (12+3)\sqrt{9^2+{12}^2}$

$A=\pi \times 15\times 15=707.14c{m}^2$

Volume of Bucket= Volume of frustum

$V=\frac{1}{3}\pi h(R^2+r^2+R\times r)$

$V=\frac{1}{3}\pi \times 12({12}^2+3^2+12\times 3)$

$V=2375c{m}^3$