SOLUTION: In a triangle PQR, p=5cm, q=7cm and angle PRQ=60 degree. Find the value of r, correct to 2 decimal places

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Question 1133264: In a triangle PQR, p=5cm, q=7cm and angle PRQ=60 degree. Find the value of r, correct to 2 decimal places
Answer by ikleyn(52798) About Me  (Show Source):
You can put this solution on YOUR website!
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Use the Law of cosine


r = sqrt%285%5E2+%2B+7%5E2+-+2%2A5%2A7%2Acos%2860%5Eo%29%29 = sqrt%285%5E2+%2B+7%5E2+-+2%2A5%2A7%2A0.5%29 = 6.24 (correct to 2 decimal places.)