A map has a scale of 1 cm to 2.5 km. Two villages are 8 cm apart on…

Step by step

The question

Question: with the scale 1 cm : 2.5 km, how long is 8 cm on the map in real life?

The scale means: 1 cm on the map is 2.5 km for real.

1 Multiply both sides

On the map we have 8 cm.

That is 8 times 1 cm.

So the real length is 8 times 2.5 km too.

If 1 cm is 2.5 km, then 8 cm is 8 times as much.

So we multiply both sides, the map side and the real side, by the same number, 8.

Forget the points: 25 times 8 is 200.

2.5 is 25 tenths.

So the answer is 200 tenths.

That is 1 digit after the point: 20.0, which is 20.

So the real length is 20 km.

2 Check

Let's check: go back.

20 divided by 2.5 should give the map length, 8.

We get it again.

So 20 km is right!

Let's look back.

First: multiply both sides.

Last: check.