To measure distance on a chart, you always use the following scale?

• A. Latitude scale
• B. Longitude scale
• C. Distance scale
• D. Scale bar

Answer: (A)

Measuring distance on a chart relies on the chart’s scale—the relationship between a length on the map and the real-world distance it represents. The most practical tool for this is the scale bar, a graphic ruler printed on the chart that shows how far a given length on the map corresponds to in miles or kilometers. You can directly compare or lay a ruler along a measured line and read off the distance from the bar.

Latitude and longitude are angular measurements used to locate positions, not direct distances. Distances inferred from differences in latitude or longitude would require converting angular units to linear units and depend on your position on the globe, so they’re not the straightforward method you use to measure distance on a chart. The term distance scale isn’t a standard, direct measuring tool you’d rely on in practice. So the scale bar is the best answer for measuring distance on a chart.