$\"\"$

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From the diagram a = 9, b = 4.5 and $\"\"$ .

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Law of cosines for cos C : $\"\"$

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$\"\"$ (Substitute : a = 9, b = 4.5 and $\"\"$ )

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$\"\"$ ( $\"\"$ )

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$\"\"$ (Simplify)

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$\"\"$ (Take square root each side)

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$\"\"$ (Simplify) $\"\"$

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Law of cosines for cos A : $\"\"$

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$\"\"$ (Substitute : a = 9, b = 4.5 and c = 11.02)

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$\"\"$ (Simplify)

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$\"\"$

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$\"\"$ (Simplify)

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$\"\"$ ( $\"\"$ ) $\"\"$

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Law of cosines for cos B : $\"\"$

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$\"\"$ (Replace a = 9, b = 4.5 and c = 11.02)

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$\"\"$ (Simplify)

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$\"\"$

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$\"\"$ (Simplify)

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$\"\"$ ( $\"\"$ ) $\"\"$

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The solution is $\"\"$ , $\"\"$ and $\"\"$ .