Conversion between metric and imperial units - WJECCentimetres and millimetres to inches and feet

Why is it that we seem to know our height in feet and inches but we don’t use this measurement for anything else?

The old imperial system of measurement has been almost completely removed from society, but there are certain places it remains. Height is just one of these examples.

Nevertheless, we need a way to convert between cm and inches, so we use the following approximation:

1 inch = 2.5 cm (the exact value is 2.54).

It is also useful to remember that a 30 cm ruler is approximately 12 inches long or 1 foot.

We need a way to change from feet into cm too. 1 foot is 12 inches or approximately 30.5 cm, so to convert from cm to feet we divide by 30.5.