$\"\"$ \ \

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Let $\"\"$ and $\"\"$ be the three segments of the highway around the bay.

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$\"\"$

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The length of the highway is $\"\"$ .

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Consider $\"\"$ .

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$\"\"$

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$\"\"$ .

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$\"\"$

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Consider $\"\"$ .

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$\"\"$

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$\"\"$ .

\

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Consider $\"\"$ .

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$\"\"$

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$\"\"$ .

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\ \

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Consider $\"\"$ .

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$\"\"$

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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 length of the highway is $\"\"$ .

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

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$\"\"$

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$\"\"$ .

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$\"\"$

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The length of the highway is $\"\"$ . \ \