 # Calculation from Maps

Lesson

This chapter is about using the scale given on a map to calculate the actual distances between pairs of places.

Scale information is usually given in the form of a short line or bar whose length corresponds to a particular real distance. In the questions that go with this chapter, you will see that the scale bar is calibrated in both kilometres and miles. In some cases, you will need to check with a ruler to determine what units are assumed in the given information.

#### Example 1 In this map, the distance between the two locations marked as black dots is approximately $2.5$2.5 of the $200$200-km scale units. This means the actual distance on the ground is $2.5\times200=500$2.5×200=500 km.

If, instead, we use the $100$100-mile scale unit, measurement with a ruler shows that there are roughly $3$3 of these units in the distance. Thus, in miles, the distance is $3\times100=300$3×100=300 miles.

D

### Outcomes

#### MS1-12-3

interprets the results of measurements and calculations and makes judgements about their reasonableness