document.write( "Question 1133678: The diagonal of a rectangle field is y^2+16cm and one side is 8y cm. For what value of y the perimeter of the rectangle will be 62 cm
\n" ); document.write( "I. 3cm II.5cm III.7cm
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Algebra.Com's Answer #750956 by MathLover1(20849)\"\" \"About 
You can put this solution on YOUR website!
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\n" ); document.write( "\n" ); document.write( "The diagonal of a rectangle field is \"y%5E2%2B16\"cm and one side is \"8y\" cm. For what value of y the perimeter of the rectangle will be \"62+\"cm\r
\n" ); document.write( "\n" ); document.write( "To find the width, multiply the length that you have been given by\"+2\", and subtract the result from the perimeter. You now have the total length for the remaining \"2\" sides. This number divided by \"2\" is the width.\r
\n" ); document.write( "\n" ); document.write( "\"2W=+62-2L\"\r
\n" ); document.write( "\n" ); document.write( "\"2W=+62-2%2A8y\"\r
\n" ); document.write( "\n" ); document.write( "\"W=+62%2F2-2%2A8y%2F2\"\r
\n" ); document.write( "\n" ); document.write( "\"W=+31-8y\"\r
\n" ); document.write( "\n" ); document.write( "diagonal cuts rectangle into two right triangles, so if\r
\n" ); document.write( "\n" ); document.write( "\"d=y%5E2%2B16\", \"L=8y\", and \"W=+31-8y\" we have \r
\n" ); document.write( "\n" ); document.write( "\"d%5E2=L%5E2%2BW%5E2+\"\r
\n" ); document.write( "\n" ); document.write( "\"d=sqrt%28L%5E2%2BW%5E2%29\"\r
\n" ); document.write( "\n" ); document.write( "\"y%5E2%2B16=sqrt%28%288y%29%5E2%2B%2831-8y%29%5E2%29\"\r
\n" ); document.write( "\n" ); document.write( "\"y%5E2%2B16=sqrt%2864y%5E2%2B64y%5E2+-+496+y+%2B+961%29\"\r
\n" ); document.write( "\n" ); document.write( "\"y%5E2%2B16=sqrt%28128y%5E2+-+496+y+%2B+961%29\"\r
\n" ); document.write( "\n" ); document.write( "\"%28y%5E2%2B16%29%5E2=%28sqrt%28128y%5E2+-+496+y+%2B+961%29%29%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"y%5E4+%2B+32+y%5E2+%2B+256=+128y%5E2+-+496+y+%2B+961+\"\r
\n" ); document.write( "\n" ); document.write( "\"128y%5E2-y%5E4++-+496+y-+32+y%5E2%2B+961+-256=0\"\r
\n" ); document.write( "\n" ); document.write( "\"-y%5E4+%2B+96+y%5E2+-+496+y+%2B+705+=+0\"\r
\n" ); document.write( "\n" ); document.write( "\"-%28y+-+5%29+%28y+-+3%29+%28y+%28y+%2B+8%29+-+47%29+=+0\"\r
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\n" ); document.write( "\n" ); document.write( "if \"-%28y+-+5%29=0+\"=>\"-y%2B5=0\"=>\"5=y\"....one solution to use\r
\n" ); document.write( "\n" ); document.write( "if \"%28y+-+3%29=0\"=>\"y=3\"....another solution to use\r
\n" ); document.write( "\n" ); document.write( "\"%28y+%28y+%2B+8%29+-+47%29+=+0\"=>\"y%5E2+%2B+8y+-+47=+0\"=>\"y+=+-4+-+3+sqrt%287%29\" , \"y+=+3+sqrt%287%29+-+4\".....disregard these solutions\r
\n" ); document.write( "\n" ); document.write( "go with:\r
\n" ); document.write( "\n" ); document.write( "=>\"y=5\"
\n" ); document.write( "\"L=8%2A5\"
\n" ); document.write( "\"L=40cm\"
\n" ); document.write( "and
\n" ); document.write( " \"W=+31-8%2A5\"
\n" ); document.write( "\"W=+31-40\"
\n" ); document.write( "\"W=+-9cm\"=> disregard negative solution\r
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\n" ); document.write( "\n" ); document.write( "go with:\r
\n" ); document.write( "\n" ); document.write( "=>\"y=3\"
\n" ); document.write( "\"L=8%2A3\"
\n" ); document.write( "\"L=24cm\"
\n" ); document.write( "and
\n" ); document.write( " \"W=+31-8%2A3\"
\n" ); document.write( "\"W=+31-24\"
\n" ); document.write( "\"W=+7cm\"\r
\n" ); document.write( "\n" ); document.write( "check the perimeter:\r
\n" ); document.write( "\n" ); document.write( "\"2%2A24cm%2B2%2A7cm=62cm\"
\n" ); document.write( "\"48cm%2B14cm=62cm\"
\n" ); document.write( "\"62cm=62cm\"\r
\n" ); document.write( "\n" ); document.write( "diagonal:
\n" ); document.write( "\"d=y%5E2%2B16\"
\n" ); document.write( "\"d=3%5E2%2B16\"
\n" ); document.write( "\"d=25\"\r
\n" ); document.write( "\n" ); document.write( "\"d=sqrt%28L%5E2%2BW%5E2%29\"
\n" ); document.write( "\"25=sqrt%2824%5E2%2B7%5E2%29\"
\n" ); document.write( "\"25=sqrt%28625%29\"
\n" ); document.write( "\"25=25\"\r
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\n" ); document.write( "\n" ); document.write( "so, your answer is: I. \"3cm\"\r
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