Question

The shape of the wooden block is of the form of frustum of a cone. Determine the height of a frustum of a cone if the radii of the ends are 23 m and 4 m and its volume is 2,400 $m^3$.

• A. 0.5 m
• B. 1.5 m
• C. 2.5 m
• D. 3.5 m

Answer 1

The correct option is D 3.5 m

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

R = 23 m, r = 4 cm, Volume = 2,400 $m^3$

$2,400=\frac{\pi \times h}{3}({23}^2+23\times 4+4^2)$

$7200=\pi h(529+92+16)$

$7200/637\pi =h$

h = $3.5m$