Question

The height of the frustum cone is 60 cm. The area of the top and bottom circle of the cone is 10 cm${}^2$ and 10 cm${}^2$ respectively. Find its volume.

• A. 500 cm${}^3$
• B. 600 cm${}^3$
• C. 700 cm${}^3$
• D. 800 cm${}^3$

Answer 1

Answer: (B)

600 cm${}^3$

Volume of the frustum cone is V = $\frac{h}{3}[\pi R^2+\pi r^2+\sqrt{\left(\pi R^2\right)\left(\pi r^2\right)}$]

Area of the top cone = 10 cm${}^2$

Area of the bottom cone = 10 cm${}^2$

Height = 60 cm

Volume = $\frac{60}{3}[10+10+\sqrt{10\ast 10}$ ]

$=20[20+\sqrt{100}]$

$=20[20+10]$

$=20\times 30$

$=600c{m}^3$