Which angle must be known to find a missing side using the Cosine Rule?
The included angle (the angle between the two known sides).
A non-included angle (an angle not between the two known sides).
The exterior angle (the angle outside the triangle).
The opposite angle (the angle opposite one of the known sides).
Flashcards for Edexcel GCSE Maths The Cosine Rule, covering the key formulae, methods and definitions you need to recall for Paper 1, Paper 2 and Paper 3. 22 cards, matched to the Edexcel GCSE Maths (1MA1) specification.
