document.write( "Question 173453: if the perimeter of a rectangle is 20 feet anf the diagonal is 2 square root 13 feet, then what are the length and width? \n" ); document.write( "
Algebra.Com's Answer #128311 by solver91311(24713)\"\" \"About 
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The perimeter of a rectangle is given by \"P=2l%2B2w\", so we know that \"2l%2B2w=20\".\r
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\n" ); document.write( "\n" ); document.write( "Solving for \"l\":\r
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\n" ); document.write( "\n" ); document.write( "\"2l%2B2w=20\"\r
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\n" ); document.write( "\n" ); document.write( "\"2l=20-2w\"\r
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\n" ); document.write( "\n" ); document.write( "\"l=10-w\"\r
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\n" ); document.write( "\n" ); document.write( "The measure of a diagonal of a rectangle in terms of the length and width is given by the Pythagorean Theorem:\r
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\n" ); document.write( "\n" ); document.write( "\"d=sqrt%28l%5E2%2Bw%5E2%29\" where \"d\" is the measure of the diagonal.\r
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\n" ); document.write( "\n" ); document.write( "But we know that: \"sqrt%28l%5E2%2Bw%5E2%29=2sqrt%2813%29\"\r
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\n" ); document.write( "\n" ); document.write( "Square both sides:\r
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\n" ); document.write( "\n" ); document.write( "\"l%5E2%2Bw%5E2=4%2A13=52\"\r
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\n" ); document.write( "\n" ); document.write( "Now substitute the expression for \"l\" in terms of \"w\" developed earlier:\r
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\n" ); document.write( "\n" ); document.write( "\"%2810-w%29%5E2%2Bw%5E2=4%2A13=52\"\r
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\n" ); document.write( "\n" ); document.write( "Expand, collect terms, and put into standard form for a quadratic:\r
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\n" ); document.write( "\n" ); document.write( "\"100-20w%2Bw%5E2%2Bw%5E2=52\"\r
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\n" ); document.write( "\n" ); document.write( "\"2w%5E2-20w%2B48=0\"\r
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\n" ); document.write( "\n" ); document.write( "Divide through by \"2\"\r
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\n" ); document.write( "\n" ); document.write( "\"w%5E2-10w%2B24=0\"\r
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\n" ); document.write( "\n" ); document.write( "Leaving you with a factorable quadratic to solve. Hint: \"-4%2A-6=24\" and \"-4-6=-10\"\r
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\n" ); document.write( "\n" ); document.write( "Since you are solving for the width, pick the smaller of the two roots as your width and calculate the length from \"l=10-w\" (which you will find is the other root of your quadratic)
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