$\"\"$

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The area of the oblique triangle is $\"\"$ .

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Consider $\"\"$ .

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Square on each side.

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$\"\"$

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Extract square root of each side.

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$\"\"$

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Pythagorean identity : $\"\"$ .

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$\"\"$

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$\"\"$

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Consider $\"\"$ .

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Law of cosines : $\"\"$ .

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$\"\"$

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Thus, $\"\"$ .

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$\"\"$

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Consider $\"\"$ .

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Law of cosines : $\"\"$ .

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$\"\"$

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Thus, $\"\"$ .

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$\"\"$

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Substitute $\"\"$ and $\"\"$ in equation (1).

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$\"\"$

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$\"\"$

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Area of the triangle is $\"\"$ .