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(d) By using a representative fractional (ratio) scale, ground
distance from point A to B can be calculated as in the
measurement of straight line distance using a piece of paper.

If the representative fractional scale is 1: 50000 and a map
distance measured between the two knots is 3cm, then the
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ground distance between points A and B is 1.5 km.

2. Using a pair of dividers

The following are the steps to measure distance on a map using a
pair of dividers:

(a) Identify two points, namely point A and B as shown in Figure 16.

Figure 16: The curved distance to be measured from point A to B

(b) Divide the distance that needs to be measured into shorter,
straight segments and mark them as shown in Figure 17

Figure 17: The divided straight segments to be measured from point A to B

(c) Use a pair divider to obtain the length of each segment one after
the other, as shown in Figure 18

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GEOGRAPHY AND THE ENVIRONMENT-STD 4.indd 67 21/11/2024 16:58