Formulae

A formula is a rule written in symbols, and the whole point of a rule is that you can use it whichever way you need. Sometimes you know the radius and want the area; sometimes you know the area and want the radius. Sometimes you know a physics formula but the quantity you actually need is buried in the middle of it. In this lesson you learn to rearrange any formula to isolate the quantity you want, and to substitute values in safely — the exact skill an engineer uses to size a beam, a nurse uses to work out a dosage, and you will use in nearly every science and maths paper from here to A/L.