Which unit would be most appropriate for measuring the distance between towns?

• A. Centimeters
• B. Meters
• C. Millimeters
• D. Kilometers

Answer: (D)

For measuring distances between towns, you want a unit that keeps the numbers easy to read. Centimeters and millimeters are far too small for long distances, so they would yield huge numbers. Meters can work, but a typical town-to-town distance would still be a large number in meters (for example, 20 kilometers is 20,000 meters), which isn’t as convenient. Kilometers fit the scale perfectly: 1 kilometer equals 1,000 meters, so you can express road distances in a straightforward, intuitive way (such as 20 or 25 kilometers). That’s why kilometers are the most appropriate unit for this purpose.