$\"\"$

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The angles of triangle is $\"\"$ .

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The sides of the triangle are $\"\"$ and $\"\"$ .

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Law of cosines : $\"\"$ .

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$\"\"$

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Law of cosines : $\"\"$ .

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$\"\"$

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$\"\"$

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The sum of angles in a triangle is $\"\"$ .

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Substitute corresponding values.

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$\"\"$

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Therefore $\"\"$ , $\"\"$ and $\"\"$ .

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$\"\"$

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$\"\"$ , $\"\"$ and $\"\"$ .