5 Relating the SI and imperial systems of measurement

This section of the week has two aims: to give a better idea of the size of unfamiliar units and to provide more practice at converting between units. You can’t get too much practice at this as it is one of those skills that just needs a bit of extra work to perfect.

In order to be able to do this, you need to know in a bit more detail about how units in the SI relate to units in the imperial system. So, listed below are some of the more common conversion factors:

• 1 metre = 39.4 inches
• 1 metre = 1.1 yards
• 1 yard = 0.9 metres
• 1 mile = 1.6 kilometres
• 1 inch = 2.54 cm.

A practical way that you can help yourself become more familiar with units that you don’t usually use is to use them in your everyday life. So, for example, if you measure materials for DIY projects in millimetres, see what this would be if you used inches instead. This should help you to get a much better feel for the units than just looking at a lot of numbers!

Now it is time to use this information.