Question

The scale on a map is 1:200 000.

Work out the number of kilometres represented by 2.5 cm on the map.

I've never done a question like this before. If you can help I would be really grateful.

Answer 1

Notice the scale of 1 : 200000 has no units.
that means we could use any units, that is,
1 cm on the map represents 200000 cm
1 mm on the map represents 200000 mm
1 inch on the map represents 200000 inches

so if 1 cm represents 200000 cm
then 2.5 cm represents 2.5(200000) cm
which is 500000 cm
which is 5000 m <----- 1 m = 100 cm
which is 5 km <----- 1 km = 1000 m

Answer 2

Scale= 1:200000
1km=100000cm
X km=200000cm
200000km/100000=2km
1/200000=2.5/y
Y= 500000cm
500000cm/100000= 5 km

Answer 3

Stuck with the answer