Scale 1 : 100, 4 cm on the drawing

Step by step

The question

Question: with the scale 1 : 100, how long is 4 cm on the drawing for real?

The scale 1 : 100 means: 1 cm on the drawing is 100 cm for real.

Everything is 100 times bigger.

1 Multiply both sides

On the drawing we have 4 cm.

That is 4 times 1 cm.

So the real length is 4 times 100 cm too.

We multiply both sides by the same number, 4.

100 times 4 is 400.

So the real length is 400 cm.

2 Change the unit

400 cm is a big number.

100 cm make 1 m, so we divide by 100.

400 divided by 100 is 4.

So it is 4 m.

3 Check

Let's check: go back.

400 divided by 100 should give the drawing length, 4.

We get it again.

So 4 m is right!

Let's look back.

First: multiply both sides.

Then: change the unit.

Last: check.