The important thing to remember about **volume** is that it has 3 dimensions. Objects extend in 3 different directions in space. So a **cuboid** that has a width of 5cm, a length of 10cm and a height of 2cm will have volume of 5 x 10 x 2 = 100cm^{2}.

The metric units of measurement for volume are “millimetres cubed”, “centimetres cubed” and “metres cubed”. We also need to know the related measures of **capacity** (i.e. how much liquid or gas something can hold) “millilitres” and “litres”.

- An object with a volume of 1cm
^{3}has a capacity of 1ml - An object with a volume of 1000cm
^{3}has a capacity of 1l.

Of course, because of the extra dimension, the conversion rates are much bigger with volume, such that:

- 1000mm
^{3}= 1cm^{3}; - 1,000,000cm
^{3}= 1m^{3}(= 1000 l )

**Exercise**

Let’s complete exercise 5D on page 76 of the textbook:

The answers are below: