Question

If the frustum of a cone has a height of $6cm$ and radius of $5cm$ and $9cm$ respectively; then its cubical volume will be .............. ${cm}^3$.

• A. $320\pi$
• B. $151\pi$
• C. $302\pi$
• D. $98\pi$

Answer 1

Answer: (C)

$302\pi$

Given $h=6cm,R_1=9cm$ and $R_2=5cm$
Volume of the frustrum of cone $=\frac{1}{3}\pi h(R_1^2+R_2^2+R_1{R}_2)$
volume of the frustrum of cone $=\frac{1}{3}\times \pi \times 6({\left(9\right)}^2+{\left(5\right)}^2+(9\left)\right(5\left)\right)=302\pi$