Map scale 1 cm : 5 km, 2.5 cm on the map

Step by step

The question

Question: with the scale 1 cm : 5 km, how long is 2.5 cm on the map for real?

The scale means: 1 cm on the map is 5 km for real.

1 Multiply both sides

On the map we have 2.5 cm.

That is 2.5 times 1 cm.

So the real length is 2.5 times 5 km too.

We multiply both sides by the same number, 2.5.

Forget the points: 5 times 25 is 125.

The numbers have 1 digit after the point.

So the answer has 1 too: 12.5.

So the real length is 12.5 km.

2 Check

Let's check: go back.

12.5 divided by 5 should give the map length, 2.5.

We get it again.

So 12.5 km is right!

Let's look back.

First: multiply both sides.

Last: check.