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Find the length of \( x \) in a right-angled triangle given one leg and the hypotenuse.
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Apply the Pythagorean theorem
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Use the Pythagorean theorem to relate the squares of the sides of the triangle.
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The Pythagorean theorem states \( a^2 + b^2 = c^2 \), where \( a \) and \( b \) are the legs, and \( c \) is the hypotenuse. Substituting the given values: \( 3^2 + x^2 = 7^2 \).
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Simplify the equation
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Simplify the squares and isolate \( x^2 \).
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Calculating: \( 9 + x^2 = 49 \). Subtracting 9 from both sides gives \( x^2 = 40 \).
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Solve for \( x \)
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Take the square root of both sides to find \( x \).
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\( x = \sqrt{40} = \sqrt{4 \cdot 10} = 2\sqrt{10} \). Thus, the length of \( x \) is \( 2\sqrt{10} \).
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The length of \( x \) is \( 2\sqrt{10} \).
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x = 2√10