document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=210974>Question 210974</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A rectangular skating rink measures 40 m by 20 m. Next year the rink is to<BR>\n" );
document.write( "be doubled in area by extending each side by the same amount. Determine how<BR>\n" );
document.write( "much each side should be extended, to the nearest tenth of a meter. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #159482 by </B><A HREF=/tutors/aboutme.mpl?userid=MathTherapy><B>MathTherapy(10552)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=MathTherapy><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=MathTherapy><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=159482\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A rectangular skating rink measures 40 m by 20 m. Next year the rink is to<BR>\n" );
document.write( "be doubled in area by extending each side by the same amount. Determine how<BR>\n" );
document.write( "much each side should be extended, to the nearest tenth of a meter.\r<BR>\n" );
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document.write( "Let the amount that each side will be extended by be x\r<BR>\n" );
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document.write( "Then we'll have: (40 + x)(20 + x) = 2(800)\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=800+%2B+60x+%2B+x%5E2+=+1600 ALIGN=MIDDLE  ALT=\"800+%2B+60x+%2B+x%5E2+=+1600\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%5E2+%2B+60x+-+800+=+0 ALIGN=MIDDLE  ALT=\"x%5E2+%2B+60x+-+800+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Since this cannot be easily factored, we use the quadratic equation to solve\r<BR>\n" );
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document.write( "a  = 1  ;  b  =  60   ;  c = - 800\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > \r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%28-60+%2B-+sqrt%28+60%5E2-4%2A1%2A-800%29%29%2F%282%2A1%29 ALIGN=MIDDLE  ALT=\"x+=+%28-60+%2B-+sqrt%28+60%5E2-4%2A1%2A-800%29%29%2F%282%2A1%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > \r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%28-60+%2B-+sqrt%283600+%2B+3200%29%29%2F2 ALIGN=MIDDLE  ALT=\"x+=+%28-60+%2B-+sqrt%283600+%2B+3200%29%29%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" > \r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%28-60+%2B-+sqrt%286800%29%29%2F2 ALIGN=MIDDLE  ALT=\"x+=+%28-60+%2B-+sqrt%286800%29%29%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" > \r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%28-60+%2B+82.46%29%2F2 ALIGN=MIDDLE  ALT=\"x+=+%28-60+%2B+82.46%29%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" > or <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%28-60+-+82.46%29%2F2 ALIGN=MIDDLE  ALT=\"x+=+%28-60+-+82.46%29%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Ignore <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%28-60+-+82.46%29%2F2 ALIGN=MIDDLE  ALT=\"x+=+%28-60+-+82.46%29%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" > as measurement CANNOT be a negative number\r<BR>\n" );
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document.write( "Therefore, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%28-60+%2B+82.46%29%2F2 ALIGN=MIDDLE  ALT=\"x+=+%28-60+%2B+82.46%29%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%2822.46%29%2F2 ALIGN=MIDDLE  ALT=\"x+=+%2822.46%29%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 11.23\r<BR>\n" );
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document.write( "Each side needs to be extended <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight_green%2811.2%29 ALIGN=MIDDLE  ALT=\"highlight_green%2811.2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > meters.\r<BR>\n" );
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document.write( "Check<BR>\n" );
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document.write( "(40 + 11.2)(20 + 11.2) = 51.2 * 31.2 = 1,597.44, which is approximately 1,600 meters, or twice 800 meters. \r<BR>\n" );
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