Question

a cylindrical cardboard tube with a diameter of 8 centimeters and a height of 20 centimeters is used to package a gift.
20 cm
8 cm
what is the approximate volume of the tube? round to the nearest whole cubic centimeter.
1,005 cm³
1,340 cm³
3,351 cm³
4,021 cm³

Explanation:

Step1: Find the radius

The diameter \(d = 8\) cm, so the radius \(r=\frac{d}{2}=\frac{8}{2}=4\) cm.

Step2: Use the volume formula for a cylinder

The volume formula for a cylinder is \(V=\pi r^{2}h\). Substitute \(r = 4\) cm and \(h=20\) cm.
\(V=\pi\times(4)^{2}\times20\)
\(V=\pi\times16\times20\)
\(V = 320\pi\)
Take \(\pi\approx3.14\), then \(V\approx320\times3.14=1004.8\)

Answer:

\(1,005\mathrm{cm}^{3}\)