For part(adsbygoogle = window.adsbygoogle || []).push({}); (i), my answer is correct but my answer for(ii)seems to be a little bit out. I can't spot where I've gone wrong. Can anyone help me out?

Many thanks.

1. The problem statement, all variables and given/known data

Q.In the given triangle, find(i)[itex]|\angle abc|[/itex],(ii)[itex]|\angle bac|[/itex].

3. The attempt at a solution

(i)cos B = [itex]\frac{c^2+a^2-b^2}{2ac}[/itex] => cos B = [itex]\frac{5^2+8^2-6^2}{(2)(8)(5)}[/itex] => cos B = [itex]\frac{53}{80}[/itex] => B = secant 0.6625 => B = [itex]48^o 31'[/itex]

(ii)[itex]\frac{sin48^o 31'}{6} = \frac{sin x}{8}[/itex] => [itex]\frac{0.7491}{6} = \frac{sin x}{8}[/itex] => sin x = (8)(0.1249) => x = cosec 0.9989 => x = [itex]87^o42'[/itex]

Ans.:(From text book):(i)[itex]48^o 31'[/itex],(ii)[itex]92^o 52'[/itex]

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# Homework Help: Finding Triangle Angles with Cosine Rule

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