document.write( "Question 102898: A rectangle has a diagonal that is 3.6 feet longer than the length and 7.1 feet longer than the width. What are the dimensions of the rectangle? \n" ); document.write( "
Algebra.Com's Answer #74853 by Fombitz(32388)\"\" \"About 
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A rectangle has a diagonal that is 3.6 feet longer than the length and 7.1 feet longer than the width. What are the dimensions of the rectangle?
\n" ); document.write( "Let's write down what you know so far:
\n" ); document.write( "1. \"D=3.6+%2B+L\"
\n" ); document.write( "2. \"D=7.1+%2B+W\"
\n" ); document.write( "The diagonal of a rectangle also follows the Pythagorean theorem since the width and length form the sides of a right triangle with a hypotenuse that is the diagonal. Therefore,
\n" ); document.write( "3. \"D%5E2+=+L%5E2+%2B+W%5E2\"
\n" ); document.write( "You can use equations (1) and (2) to come up with a relationship between L and W and use that in equation (3).
\n" ); document.write( "Since \"3.6%2BL\" and \"7.1%2BL\" are both equal to \"D\", then they are equal to each other.
\n" ); document.write( "\"3.6%2BL=7.1%2BW\"
\n" ); document.write( "\"3.6-3.6%2BL=7.1-3.6%2BW\" Additive inverse of 3.6
\n" ); document.write( "4.\"L=3.5%2BW\"
\n" ); document.write( "Now use equation (3) and substitute using this latest result (4) and equation (2) to get an equation that only involves the variable W.
\n" ); document.write( "3. \"D%5E2+=+L%5E2+%2B+W%5E2\"
\n" ); document.write( "\"%287.1%2BW%29%5E2=%283.5%2BW%29%5E2%2BW%5E2\"Substitute.
\n" ); document.write( "Expand.
\n" ); document.write( "\"50.41%2B14.2%2AW%2BW%5E2=+12.25%2B7%2AW%2B2W%5E2\" Simplify both sides.
\n" ); document.write( "
\n" ); document.write( "\"38.16%2B7.2%2AW-W%5E2=0\"
\n" ); document.write( "Use the quadratic formula to find the roots of the equation:
\n" ); document.write( "\"W+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"
\n" ); document.write( "where \"a+=+-1\", \"b+=+7.2\", and \"c+=+38.16\"
\n" ); document.write( "\"W+=+%28-7.2+%2B-+sqrt%28+7.2%5E2-4%2A%28-1%29%2A38.16+%29%29%2F%282%2A%28-1%29%29+\"
\n" ); document.write( "\"W+=+%28-7.2+%2B-+14.3%29%2F%28-2%29+\"
\n" ); document.write( "\"W=-3.55\" and \"W=10.75\" solve the equation.
\n" ); document.write( "Since a negative width does not make sense, we'll only use the positive result.
\n" ); document.write( "\"W=10.75\"
\n" ); document.write( "Use equation (4) to get the length.
\n" ); document.write( "4.\"L=3.5%2BW\"
\n" ); document.write( "\"L=3.5%2B10.75=14.25\"
\n" ); document.write( "and finally
\n" ); document.write( "1. D=3.6+L
\n" ); document.write( "\"D=3.6%2B14.25\"
\n" ); document.write( "\"D=17.85\"
\n" ); document.write( "You can double-check your answer using the Pythagorean theorem and your length and width,
\n" ); document.write( "\"D%5E2+=+L%5E2+%2B+W%5E2\"
\n" ); document.write( "\"D%5E2+=+14.25%5E2+%2B+10.75%5E2\"
\n" ); document.write( "\"D%5E2+=+203.0625+%2B+115.5625=318.625\"
\n" ); document.write( "\"D+=+17.85\"
\n" ); document.write( "Good answer
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