document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=222747>Question 222747</A>: <I><SPAN STYLE=\"word-break: break-all;\"> It has been estimated that 900 curies of a radioactive substance introduced at a point on the surface of the open sea would spread over an area of 24000km^2 in 30 days. Assuming that the area covered by the radioactive substance is a linear function of time t and is always circular in shape, express the radius r of the contamination as a function of t.\r<BR>\n" );
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document.write( "Do not simplify the number under the radical.\r<BR>\n" );
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document.write( "I worked it out and got r=((sqr(24000/pi))/(30))*t. It appears that this is not right though. Please explain what I am doing wrong. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #166905 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=166905\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> It has been estimated that 900 curies of a radioactive substance introduced at<BR>\n" );
document.write( " a point on the surface of the open sea would spread over an area of 24000km^2 in 30 days.<BR>\n" );
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document.write( "Assuming that the area covered by the radioactive substance is a linear function of time t and<BR>\n" );
document.write( " is always circular in shape, express the radius r of the contamination as a function of t.<BR>\n" );
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document.write( "Do not simplify the number under the radical.<BR>\n" );
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document.write( "I think what you got is pretty close, here's my take on this<BR>\n" );
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document.write( "Find the value of r when t = 30 days and area = 24000<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=pi%2A%2830r%29%5E2+=+24000 ALIGN=MIDDLE  ALT=\"pi%2A%2830r%29%5E2+=+24000\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=pi%2A900%2Ar%5E2+=+24000 ALIGN=MIDDLE  ALT=\"pi%2A900%2Ar%5E2+=+24000\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5E2+=+24000%2F%28900%2Api%29 ALIGN=MIDDLE  ALT=\"r%5E2+=+24000%2F%28900%2Api%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Reduce the fraction<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5E2+=+80%2F%283%2Api%29 ALIGN=MIDDLE  ALT=\"r%5E2+=+80%2F%283%2Api%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+sqrt%2880%2F%283pi%29%29 ALIGN=MIDDLE  ALT=\"r+=+sqrt%2880%2F%283pi%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "r as a function of t<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+sqrt%2880%2F%283pi%29%29%2At ALIGN=MIDDLE  ALT=\"r+=+sqrt%2880%2F%283pi%29%29%2At\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Check this find radius when t = 30 days<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+sqrt%2880%2F%283pi%29%29%2A30 ALIGN=MIDDLE  ALT=\"r+=+sqrt%2880%2F%283pi%29%29%2A30\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "r = 87.4 km<BR>\n" );
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document.write( "Find the area using this value for r<BR>\n" );
document.write( "A = pi*87.4^2  = 24,000 sq/km; confirms our solution<BR>\n" );
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