If the scale on a map is 1cm = 1km, how do I convert 3.4cm to km?

Answer 1

3.4 * 1cm = 3.4 * 1Km

Answer 2

Do you think you should
add?
subtract?
multiply?
divide?

Answer 3

You could also look at it as a proportion.(cm/km) = (cm/km)
(1cm/1km) = (3.4cm/x)
Solve for x.
Note: this would not be the most intuitive way... but it would get the question completed if you don't see an easier way.