The diagram shows triangle PQRPQRPQR. Side PR=8.4PR = 8.4PR=8.4 km, side QR=10.5QR = 10.5QR=10.5 km, and the angle at vertex R R\,R is 52∘52^\circ52∘. The side PQ PQ\,PQ is labeled d d\,d km.
Work out the value of ddd. Give your answer to 3 significant figures.
The Cosine Rule Questions
Practise Edexcel GCSE Maths The Cosine Rule with exam-style questions for Foundation and Higher tier. 44 questions, matched to the Edexcel GCSE Maths (1MA1) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.