A triangle PQR PQR\,PQR is shown with side lengths PQ=6 kmPQ = 6\text{ km}PQ=6 km, QR=8 kmQR = 8\text{ km}QR=8 km, and PR=7 kmPR = 7\text{ km}PR=7 km. The angle at vertex Q Q\,Q is labeled PQRPQRPQR.
Work out the size of angle PQRPQRPQR.
Give your answer to the nearest degree.
The Cosine Rule Questions
Practise OCR GCSE Maths The Cosine Rule with exam-style questions for Foundation and Higher tier. 44 questions, matched to the OCR GCSE Maths (J560) specification and written in the written papers 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.