$\"\"$

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(a)

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From the given data : $\"\"$ .

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$\"\"$ .

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Pythagorean theorem : $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$ .

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$\"\"$ .

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$\"\"$

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$\"\"$ (Apply half angle formula: $\"\"$ )

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$\"\"$ (Simplify)

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$\"\"$ (Simplify)

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$\"\"$

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$\"\"$ .

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The angle $\"\"$ lies in quadrant I. $\"\"$

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(b)

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$\"\"$ and $\"\"$

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$\"\"$

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$\"\"$ (Apply half angle formula: $\"\"$ )

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$\"\"$ (Simplify)

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$\"\"$ (Simplify)

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$\"\"$ (Apply half angle formula: $\"\"$ )

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$\"\"$ (Simplify)

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

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(a) The angle $\"\"$ lies in quadrant I.

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(b) The angles are $\"\"$ , $\"\"$ and $\"\"$ .