By analysing the dimensions to the right of the equals sign, we can easily say whether a formula could be for length, area or volume.

A formula for **length **can only be one-dimensional.

This means that lengths occur on their own e.g. C = 3d or P = a + 2b

A formula for **area **can only be two-dimensional.

This means that lengths occur in pairs e.g. A = 3ab or A = a^{2} + 2ab

A formula for **volume **can only be three-dimensional.

This means that lengths occur in threes e.g. C = 5d^{3} or P = abc + 2a^{2}b