$\"\"$

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Step 1:

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Tan angle is $\"\"$ .

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Recall basic ratios of trigonometry.

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$\"\"$

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$\"\"$

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From pythagorean theorem,

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$\"\"$

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Find $\"\"$ .

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

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$\"\"$

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$\"\"$

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$\"\"$ \ \

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$\"\"$

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Solution :

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$\"\"$