How do you calculate the area of a triangle when the question tells you the length of all three sides but no angles?

  1. use the cosine rule to get angle A; cos(A) = (b2 + c2 - a2)/2bc2) Use '1/2 x a b x sin(C)' to get the area of the triangleNote: the side 'a' is the one opposite angle A
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Answered by Tom H. Maths tutor

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