$\"\"$

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Find the value of $\"\"$ .

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Observet he given figure :

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Angle $\"\"$ .

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$\"\"$ .

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Apply sine sum identity : $\"\"$ .

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$\"\"$

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Substitue the values : $\"\"$ .

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$\"\"$

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$\"\"$ .

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$\"\"$

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Option A is the correct choice.