document.write( "Question 930748: A rectangle is drawn so the width is 2 inches longer than the height. If the rectangle's diagonal measurement is 58 inches, find the height.\r
\n" ); document.write( "\n" ); document.write( "Give your answer rounded to 1 decimal place.
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Algebra.Com's Answer #565259 by rcdodds(6)\"\" \"About 
You can put this solution on YOUR website!
Well let's set this up as a system of equations.\r
\n" ); document.write( "\n" ); document.write( "Allow \"w\" to be the width.
\n" ); document.write( "Allow \"h\" to be the height.
\n" ); document.write( "Allow \"d\" to be the diagonal.\r
\n" ); document.write( "\n" ); document.write( "We know from the Pythagorean Theorem that...
\n" ); document.write( "\"a%5E2+%2B+b%5E2+=+c%5E2\"
\n" ); document.write( "but in this case
\n" ); document.write( "\"a=w\"
\n" ); document.write( "\"b=h\"
\n" ); document.write( "\"c=d=58\", so we can say that...\r
\n" ); document.write( "\n" ); document.write( "\"w%5E2+%2B+h%5E2+=+d%5E2+=+58%5E2\". Which is our first equation.
\n" ); document.write( "Our second equation comes from the \"width is 2 inches longer than the height\", which means that \"w+=+h+%2B+2\".\r
\n" ); document.write( "\n" ); document.write( "Substituting that into the first equation we can solve using algebra to find the height.\r
\n" ); document.write( "\n" ); document.write( "\"w%5E2+%2B+h%5E2+=+58%5E2\"
\n" ); document.write( "\"%28h+%2B+2%29%5E2+%2B+h%5E2+=+58%5E2\"
\n" ); document.write( "\"h%5E2+%2B+4h+%2B+4+%2B+h%5E2+=+58%5E2\"
\n" ); document.write( "\"2h%5E2+%2B+4h+%2B+4+=+58%5E2\"
\n" ); document.write( "\"2h%5E2+%2B+4h+-+3360+=+0\"
\n" ); document.write( "\"h%5E2+%2B+2h+-+1680+=+0\"
\n" ); document.write( "\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"ah%5E2%2Bbh%2Bc=0\" (in our case \"1h%5E2%2B2h%2B-1680+=+0\") has the following solutons:
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\n" ); document.write( " \"h%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca\"
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\n" ); document.write( " For these solutions to exist, the discriminant \"b%5E2-4ac\" should not be a negative number.
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\n" ); document.write( " First, we need to compute the discriminant \"b%5E2-4ac\": \"b%5E2-4ac=%282%29%5E2-4%2A1%2A-1680=6724\".
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\n" ); document.write( " Discriminant d=6724 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28-2%2B-sqrt%28+6724+%29%29%2F2%5Ca\".
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\n" ); document.write( " \"h%5B1%5D+=+%28-%282%29%2Bsqrt%28+6724+%29%29%2F2%5C1+=+40\"
\n" ); document.write( " \"h%5B2%5D+=+%28-%282%29-sqrt%28+6724+%29%29%2F2%5C1+=+-42\"
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\n" ); document.write( " Quadratic expression \"1h%5E2%2B2h%2B-1680\" can be factored:
\n" ); document.write( " \"1h%5E2%2B2h%2B-1680+=+1%28h-40%29%2A%28h--42%29\"
\n" ); document.write( " Again, the answer is: 40, -42.\n" ); document.write( "Here's your graph:
\n" ); document.write( "\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B2%2Ax%2B-1680+%29\"

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\n" ); document.write( "\n" ); document.write( "Rounding this to one decimal place, we get our final answer to be 40 inches.
\n" ); document.write( "Note that we ignore the negative result from the quadratic formula because you can't have a negative distance.
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