\"\"

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The side lengths of a right triangle are \"b ; \"a

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Apply Pythagorean theorem: \"a

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\"a                              (Substitute 45 for b and 51 for c)

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\"a                        (Evaluate powers: \"45)\"\"

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\"a (Subtract 2025 from each side)

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\"a                                       (Subtract: \"2601)

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\"square                                (Take square root each side)

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\"\"                                 (Evaluate power \"\")

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

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The unknown length of \"a.