the ratio of a case is basically the main point of the judgement. It is usually one sentence or two from the judgement, which best expresses the themes and outcomes of the decision. The ratio should be a legal principle which could be applied in another fact scenario, not some information on the specific facts of this case. You can find it by asking yourself which main points of law were being debated, look at what the court decided on each of those points, and decide which point is most important to the development of the case. Don’t worry though, finding a ratio is a skill which you will learn with practise throughout law school, so don’t fret if you can’t work it out right away!

best of luck with your studies!