A triangle has sides A, B, and C. Sides A and B are of lengths $2$ and $7$ , respectively, and the angle between A and B is $(7pi)/8$ . What is the length of side C?

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Answer 1 · 2016-06-30T02:20:29

Given
$"Side A"=2,"Side B"=7$

$theta="Angle between" A & B=(7pi)/8$
$"Side C"= ?$

We know

$C^2=A^2+B^2-2ABcostheta$

$=>C^2=2^2+7^2-2*2*7*cos(7pi/8)$

$=>C=sqrt(2^2+7^2-2*2*7*cos(7pi/8))$

$=>C~~8.88$

A triangle has sides A, B, and C. Sides A and B are of lengths 22 and 77, respectively, and the angle between A and B is (7pi)/8 (7pi)/8 . What is the length of side C?