As all (well, at least those that can remember) 15+ year old’s know, to find the length of a side of a non-right angled triangle you can’t use Pythagoras theorem and instead require the so called ‘Cosine Rule’.
As all (well, at least those that can remember) 15+ year old’s know, to find the length of a side of a non-right angled triangle you can’t use Pythagoras theorem and instead require the so called ‘Cosine Rule’.