document.write( "Question 657795: Consider a rectangle that has a diagonal of 20 feet and a perimeter of 52 feet. Find the area of this rectangle. \n" ); document.write( "
Algebra.Com's Answer #410032 by kevwill(135)\"\" \"About 
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let l be the length of the rectangle and w be the width of the rectangle. With the diagonal being 20 feet long, using the Pythagorean Theormem, we get
\n" ); document.write( "\"sqrt%28l%5E2+%2B+w%5E2%29+=+20\"
\n" ); document.write( "\"l%5E2+%2B+w%5E2+=+400\"\r
\n" ); document.write( "\n" ); document.write( "With a perimeter of 52 feet, we have
\n" ); document.write( "\"2%2Al+%2B+2%2Aw+=+52\"
\n" ); document.write( "\"l+%2B+w+=+26\"
\n" ); document.write( "\"l+=+26+-+w\"\r
\n" ); document.write( "\n" ); document.write( "Substituting, we get
\n" ); document.write( "\"%2826-w%29%5E2+%2B+w%5E2+=+400\"
\n" ); document.write( "\"%28676-52w%2Bw%5E2%29+%2B+w%5E2+=+400\"
\n" ); document.write( "\"2%2Aw%5E2+-+52w+%2B+276+=+0\"\r
\n" ); document.write( "\n" ); document.write( "We can solve for w using the quadratic equation with a=2, b=-52, and c=276:\r
\n" ); document.write( "\n" ); document.write( "\"w+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"
\n" ); document.write( "\"w+=+%28-%28-52%29+%2B-+sqrt%28+%28-52%29%5E2-4%2A2%2A276%29%29%2F%282%2A2%29+\"
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\n" ); document.write( "\"w+=+13+%2B-+sqrt%2831%29+\"
\n" ); document.write( "\"+w+=+13+%2B+sqrt%2831%29+\" and \"+l+=+26-w+=+26+-+%2813%2Bsqrt%2831%29%29+=+13-sqrt%2831%29+\", or
\n" ); document.write( "\"+w+=+13+-+sqrt%2831%29+\" and \"+l+=+26-w+=+26+-+%2813-sqrt%2831%29%29+=+13%2Bsqrt%2831%29+\"
\n" ); document.write( "Both of these are basically the same solution with the l and w values being switched. So the area is:
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\n" ); document.write( "\n" ); document.write( "The area is 138 square feet.\r
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