Formulas (H)

There are two key skills about using formula. The first is substitution – when you are given the value of a variable, you replace the variable with this number each time it occurs in the formula.

Substitution occurs in many other areas of algebra, so you should already be familiar with it.

The second skill is rearranging a formula. Formulae tend to be stated and remembered in one arrangement. For instance, you should recall that the formula for the volume of a cylinder is V = πr²h. This is fine if you know r and h. But what if you are given the volume, V, and the height, h, and need to find r? You will need to rearrange the formula so that r is the subject. Can you master it?