Question

The volume of frustum of a cone is 600 m${}^3$. The area of the bottom circle of the cone is 10 m${}^2$ and the area of the top circle of the cone is 10 m${}^2$. Find its height.

• A. 60 m
• B. 70 m
• C. 50 m
• D. 40 m

Answer 1

Answer: (A)

60 m

Volume of the frustum cone is V = $\frac{h}{3}[A_1+A_2+\sqrt{A_1{A}_2}$]

Area of the bottom cone, A${}_1$ = 10 m${}^2$

Area of the top cone, A${}_2$ = 10 m${}^2$

Height = ?

Volume = 600 m${}^3$

$600=h/3[10+10+\sqrt{10\times 10}]$

$600\times 3=h[20+\sqrt{100}]$

$1,800=h[20+10]$

$1,800/30=h$

$h=60m$