Question

Enter the number that belongs in the green box

Answer 1

Check the picture below.

`\textit{Law of Cosines}\\\\ \cfrac{a^2+b^2-c^2}{2ab}=\cos(C)\implies \cos^(-1)\left(\cfrac{a^2+b^2-c^2}{2ab}\right)=\measuredangle C \\\\[-0.35em] ~\dotfill\\\\ \cos^(-1)\left(\cfrac{10^2+4^2-7^2}{2(10)(4)}\right)=\measuredangle A \implies \cos^(-1)\left(\cfrac{ 67 }{ 80 }\right)=\measuredangle A \\\\\\ \cos^(-1)(0.8375) = \measuredangle A \implies 33.12^o \approx \measuredangle A`

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