## Prealgebra (7th Edition)

$A=4\pi \times0.5^2=1\pi$ square kilometers $A\approx \frac{22}{7}\times 1= 3.1429$ square kilometers $V=\frac{4}{3}\pi\times 0.5^3=0.16667\pi$ cubic kilometers $V\approx \frac{22}{7}\times 0.16667=0.5238$ cubic kilometers
This solid is a sphere and its volume can be calculated as: $V=\frac{4}{3}\pi r^3$ where r is the radius Here: $V=\frac{4}{3}\pi\times 0.5^3=0.16667\pi$ cubic kilometers. $V\approx \frac{22}{7}\times 0.16667=0.5238$ cubic kilometers The surface of a cylinder can be calculated as: $A=4\pi r^2$ Here: $A=4\pi \times0.5^2=1\pi$ square kilometers $A\approx \frac{22}{7}\times 1= 3.1429$