Question

The volume of the frustum of a cone is 313 cm${}^3$. The bottom and top radius are 0.2 cm and 0.1 cm. Find its height. (Use $\pi$ = 3.14). Round off your answer to nearest whole number.

• A. 4,172 cm
• B. 4,372 cm
• C. 4,472 cm
• D. 4,272 cm

Answer 1

The correct option is D 4,272 cm

Volume of the frustum cone is V = $\frac{\pi h}{3}(R^2+Rr+r^2)$

R = 0.2 cm, r = 0.1 cm, h = ?

Volume = 313 $c{m}^3$

$313=(3.14\times h)/\left(3\right)[{0.2}^2+0.2\times 0.1+{0.1}^2]$

$313\times 3/3.14=h[0.04+0.02+0.01]$

$299.044=h\left[0.07\right]$

$4,272=h$

$h=4,272cm$