Question

what is a length of a river that is (a) 7, 5 cm (b) 9, 2 cm (c) 1, 2 . On a map that is 1 : 25 000 and 1 : 50 000​

Answer 1

Answer:

Converting measurements on a map

We saw above that if a map has a scale of 1 : 50000, then 1 cm on the map is 50000 cm in real life.

(a) Imagine we have measured a distance as 3 cm on this map, and we want to find out how far this is in real life.

To work out the distance in real life, we need to multiply this length by 50000.

This gives 3 cm × 50000 = 150000 cm which is 1500 m or 1.5 km.

Alternatively, we could have just remembered that each 1 cm on the map is 0.5 km in real life.

Hence, 3 cm on the map must be 3 × 0.5 km = 1.5 km in real life.

(b) Now imagine we want to walk 4.5 km in real life, and we need to find out how far this is on the map.

To work out the distance on the map, we need to divide this length by 50000.

4.5 km = 4500 m = 450000 cm. Dividing 450000 cm by 50000 gives a distance on the map of 9 cm.

Alternatively, we could have just remembered that each 0.5 km in real life is 1 cm on the map.

If we divide 4.5 km by 0.5 km we get 9, so the distance on the map must be 9 cm.

Answer 2

onverting measurements on a map
We saw above that if a map has a scale of 1 : 50000, then 1 cm on the map is 50000 cm in real life.

(a) Imagine we have measured a distance as 3 cm on this map, and we want to find out how far this is in real life.
To work out the distance in real life, we need to multiply this length by 50000.
This gives 3 cm × 50000 = 150000 cm which is 1500 m or 1.5 km.
Alternatively, we could have just remembered that each 1 cm on the map is 0.5 km in real life.
Hence, 3 cm on the map must be 3 × 0.5 km = 1.5 km in real life.

(b) Now imagine we want to walk 4.5 km in real life, and we need to find out how far this is on the map.
To work out the distance on the map, we need to divide this length by 50000.
4.5 km = 4500 m = 450000 cm. Dividing 450000 cm by 50000 gives a distance on the map of 9 cm.
Alternatively, we could have just remembered that each 0.5 km in real life is 1 cm on the map.
If we divide 4.5 km by 0.5 km we get 9, so the distance on the map must be 9 cm.

In general, it is easier to work out the answer to these type of questions by
working out what 1 cm on the map is equivalent to as a real life distance.