$\"\"$

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Observe the figure:

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The values are $\"\"$ , $\"\"$ and $\"\"$ .

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Find $\"\"$ .

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$\"\"$ (Pythagorean theorem)

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$\"\"$ (Substitute $\"\"$ , $\"\"$ and $\"\"$ )

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$\"\"$ (Evaluate powers $\"\"$ and $\"\"$ )

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$\"\"$ (Addition: $\"\"$ )

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$\"\"$ (Take the square root of each side)

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$\"\"$ (Cancel square and root)

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

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Length cannot be negative,so the missing length is $\"\"$ . $\"\"$

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The length $\"\"$ is $\"\"$ .