Question

Find the surface area and volume to the nearest whole number.

Answer 1

Write out the formula for the surface area and volume of the cylinder

$\text{Surface area of a cylinder=2}\pi rh+2\pi\times r^2$$\text{Volume of a cylinder=}\pi\times r^2\times h$

Write out the given data

$\begin{gathered} r=radius=\frac{diameter}{2}=\frac{20\operatorname{km}}{2}=10\operatorname{km} \\ h=\text{height}=6\operatorname{km} \\ \pi=3.14 \end{gathered}$

Solving for the Surface area and the volume of the cylinder

$\begin{gathered} \text{Surface area=2}\times3.14\times10\times6+2\times3.14\times10^2 \\ =376.8+628=1004.8\operatorname{km}\approx1005km^2 \end{gathered}$$\begin{gathered} \text{Volume of the cylinder=3.14}\times10^2\times6 \\ =1884^{}km^{3^{}} \end{gathered}$

Hence, the surface area is 1005km² while the volume is 1884km³.