$\"\"$

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Given that $\"\"$ is a median of $\"\"$ .

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Since Y is the midpoint of $\"\"$ , $\"\"$ .

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$\"\"$ (Definition of congruent segments)

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

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$\"\"$ (Add 11 to each side)

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$\"\"$ (Subtract 2c from each side)

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$\"\"$ (Divide each side by 2) $\"\"$

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The value of c is 5.