$\"\"$

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Radius of the circle O is given by 10 units and AB = 10.

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Draw radius $\"\"$ . $\"\"$ is a right angle triangle.

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

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$\"\"$ bisects $\"\"$ (A radius perpendicular to a chord bisects it )

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$\"\"$ (Apply definition of segment bisector)

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$\"\"$ (Substitute AB = 10)

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$\"\"$ (Divide) $\"\"$

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Use the pythagorean theorem to find OX.

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$\"\"$ (Apply pythagorean theorem)

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$\"\"$ (Substitute $\"\"$ )

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$\"\"$ (Evaluate powers)

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$\"\"$ (Subtract 25 from each side)

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$\"\"$ (Subtract)

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$\"\"$ (Apply square root of each side) $\"\"$

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The value of $\"\"$ .