document.write( "Question 1202100: A dog trainer has 100 ft of fencing that will be used to create a rectangular work area for dogs. If the trainer wants to enclose an area of 504 ft2, what will be the dimensions of the work area? \n" ); document.write( "
Algebra.Com's Answer #836738 by math_tutor2020(3817)\"\" \"About 
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\n" ); document.write( "Answer: 14 ft by 36 ft\r
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\n" ); document.write( "\n" ); document.write( "Work Shown:\r
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\n" ); document.write( "\n" ); document.write( "x = width
\n" ); document.write( "y = height\r
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\n" ); document.write( "\n" ); document.write( "P = perimeter of the rectangle
\n" ); document.write( "P = 2*(width + height)
\n" ); document.write( "P = 2*(x + y)
\n" ); document.write( "Replace P with 100 as this is the perimeter, aka amount of fencing
\n" ); document.write( "100 = 2(x + y)
\n" ); document.write( "100/2 = x + y
\n" ); document.write( "50 = x + y
\n" ); document.write( "y = 50-x\r
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\n" ); document.write( "\n" ); document.write( "A = area of the rectangle
\n" ); document.write( "A = width*height
\n" ); document.write( "A = x*y
\n" ); document.write( "A = x*(50-x)
\n" ); document.write( "A = 50x-x^2
\n" ); document.write( "A = -x^2+50x
\n" ); document.write( "Plug in A = 504 which is the desired area.
\n" ); document.write( "504 = -x^2+50x
\n" ); document.write( "0 = -x^2+50x-504
\n" ); document.write( "-x^2+50x-504 = 0
\n" ); document.write( "-(x^2-50x+504) = 0
\n" ); document.write( "x^2-50x+504 = 0\r
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\n" ); document.write( "\n" ); document.write( "You could take a trial-and-error approach to factoring, but I think the quadratic formula is more efficient.
\n" ); document.write( "Plug in a = 1, b = -50, c = 504
\n" ); document.write( "\"x+=+%28-b+%2B-+sqrt%28b%5E2+-+4ac%29%29%2F%282a%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-%28-50%29+%2B-+sqrt%28%28-50%29%5E2+-+4%281%29%28504%29%29%29%2F%282%281%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%2850+%2B-+sqrt%282500-2016%29%29%2F%282%281%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%2850+%2B-+sqrt%28484%29%29%2F%282%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%2850+%2B-+22%29%2F%282%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%2850+%2B+22%29%2F%282%29+\" or \"+x+=+%2850+-+22%29%2F%282%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%2872%29%2F%282%29+\" or \"+x+=+%2828%29%2F%282%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+36+\" or \"+x+=+14\"\r
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\n" ); document.write( "\n" ); document.write( "If x = 36, then y = 50-x = 50-36 = 14
\n" ); document.write( "If x = 14, then y = 50-x = 50-14 = 36\r
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\n" ); document.write( "\n" ); document.write( "The rectangle is 14 ft by 36 ft\r
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\n" ); document.write( "\n" ); document.write( "Check:
\n" ); document.write( "Perimeter = 2*(14+36) = 2*50 = 100
\n" ); document.write( "Area = 14*36 = 504
\n" ); document.write( "The answers are confirmed.
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