$\"\"$

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Find $\"\"$ .

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Observe the figure :

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Triangles $\"\"$ and $\"\"$ are right triangles.

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The sides $\"\"$ and $\"\"$ .

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Apply Pythagorean theorem to triangle $\"\"$ .

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Pythagorean theorem : $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$ .

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$\"\"$

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Base of the right triangle $\"\"$ is $\"\"$ .

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Substitute $\"\"$ and $\"\"$ in $\"\"$ .

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$\"\"$ .

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Apply Pythagorean theorem to triangle $\"\"$ .

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Pythagorean theorem : $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$ .

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$\"\"$

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The value of $\"\"$ .