Question

What is the volume of the cylinder to the nearest whole number?

Answer 1

The formula of a cylinder:

$V=\pi r^2H$

We have the diameter d = 8m and height H = 20m.

d = 2r therefore r = 8m : 2 = 4m. Substitute:

$V=\pi(4^2)(20)=\pi(16)(20)=320\pi\ m^3\approx 320\cdot3.14\approx1005m^3$

Answer: A.) 1,005 m³

Answer 2

if the cylinder has a diameter of 8, its radius is half that, or 4.

$\bf \textit{volume of a cylinder}\\\\ V=\pi r^2 h~~ \begin{cases} r=radius\\ h=height\\[-0.5em] \hrulefill\\ r=4\\ h=20 \end{cases}\implies V=\pi (4)^2(20)\implies V=320\pi \\\\\\ V\approx 1005.3096\implies V=\stackrel{rounded}{1005}$