Question

Find the length of side x.

Give your answer to 1 decimal place.
13 cm
98°
X
17 cm

Answer 1

`\textit{Law of Cosines}\\\\ c^2 = a^2+b^2-(2ab)\cos(C)\implies c = √(a^2+b^2-(2ab)\cos(C)) \\\\[-0.35em] ~\dotfill\\\\ x = √(13^2+17^2~-~2(13)(17)\cos(98^o)) \implies x = √( 458 - 442 \cos(98^o) ) \\\\\\ x\approx√(519.51)\implies x\approx 22.8`

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