By analysing the dimensions to the right of the equals sign, we can 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 = a2 + 2ab
A formula for volume can only be three-dimensional.
This means that lengths occur in threes e.g. C = 5d3 or P = abc + 2a2b
Let's have a go at some questions.