The scale on a map is 1:25000 .(A) find the distance in kilometres between two islands represented by a distance of 20cm on the map. (B) find the distance between two towns on the map that are 10 kilometres apart?

1 Answer
Aug 9, 2018

(A) 5 km

(B) 40cm

Explanation:

Direct proportion is an easy way of working with scales.

The ratio 1 : 25000 has no specific unit, but once a unit is chosen, the unit is the same for both.

Let's use cm because that is the unit used.

1cm : 25,000cm means

1cm on the map represents :

25,000 div 100,000 = 0.25 km

Now you can compare cm and km

(A) 1/0.25 = 20/x" "(larr cm)/(larr km)

x = 0.25 xx20 = 5 km

(B) 1/0.25 = x/10" "(larr cm)/(larr km)

x = 10/0.25 = 40cm