Question
In ∆ABC, AB = 5cm, BC = 6cm and AC = 10cm then find
out the value of cos A?Solution
From Cosine rule, we get BC2 = AB2 + AC2 - 2AB.AC.cos A 36=25+100-2×5×10×Cos A 100CosA=125-36=89 cos A = 89/100 .
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