$\"\"$

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Observe the figure :

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Length between laser and circle is $\"\"$ .

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Radius of circle is $\"\"$ .

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Trigonometric ratio : $\"\"$ .

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Substitute Opposite $\"\"$ and adjacent $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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The beam must be at an angle of $\"\"$ .