Area calculations are trickier, since we have to square the numbers. We measure the distance along a property boundary as 1.7 cm. To find ground distance, we must use the map scale to convert map distance to ground distance. Notice that again we inverted the RF scale, so the units will cancel properly. We can also calculate distance from verbal and graphic scales.
Graphic scales are probably the scales most frequently used by laypersons.
You can mark off a distance on the map and compare it directly to the bar scale. You need not know how many inches or centimeters the map distance is. The main drawback of bar scales is that they are usually short compared to the map itself, and hence measuring longer distances is difficult. We must therefore used squared conversion factors when finding area from map measurements. For example, suppose we measure a rectangular piece of property that is 3 cm by 4 cm on a map.