document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=201095>Question 201095</A>: <I><SPAN STYLE=\"word-break: break-all;\"> if the radius of a circle is increase by 4 units, its original area is multiplied by 2. Find the original radius.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #151323 by </B><A HREF=/tutors/aboutme.mpl?userid=Earlsdon><B>Earlsdon(6294)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Earlsdon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=151323\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Try this:<BR>\n" );
document.write( "Original area is: <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A%5B1%5D+=+pi%2Ar%5E2 ALIGN=MIDDLE  ALT=\"A%5B1%5D+=+pi%2Ar%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The area of the new circle is:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A%5B2%5D+=+2%2AA%5B1%5D ALIGN=MIDDLE  ALT=\"A%5B2%5D+=+2%2AA%5B1%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" > and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A%5B2%5D+=+pi%2A%28r%2B4%29%5E2 ALIGN=MIDDLE  ALT=\"A%5B2%5D+=+pi%2A%28r%2B4%29%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" >, so...<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=pi%2A%28r%2B4%29%5E2+=+2%2Api%2Ar%5E2 ALIGN=MIDDLE  ALT=\"pi%2A%28r%2B4%29%5E2+=+2%2Api%2Ar%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=pi%2A%28r%5E2%2B8r%2B16%29+=+2%2Api%2Ar%5E2 ALIGN=MIDDLE  ALT=\"pi%2A%28r%5E2%2B8r%2B16%29+=+2%2Api%2Ar%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > Divide both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=pi ALIGN=MIDDLE  ALT=\"pi\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5E2%2B8r%2B16+=+2%2Ar%5E2 ALIGN=MIDDLE  ALT=\"r%5E2%2B8r%2B16+=+2%2Ar%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > Subtract <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5E2 ALIGN=MIDDLE  ALT=\"r%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > from both sides.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=8r%2B16+=+r%5E2 ALIGN=MIDDLE  ALT=\"8r%2B16+=+r%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > Rewrite as a quadratic equation in standard form:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5E2-8r-16=0 ALIGN=MIDDLE  ALT=\"r%5E2-8r-16=0\"   DISABLED_style= \"max-width:90%; height:auto;\" > Solve using the quadratic formula: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a ALIGN=MIDDLE  ALT=\"r+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a\"   DISABLED_style= \"max-width:90%; height:auto;\" > where: a = 1, b = -8, and c = -16.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+%28-%28-8%29%2B-sqrt%28%28-8%29%5E2-4%281%29%28-16%29%29%29%2F2%281%29 ALIGN=MIDDLE  ALT=\"r+=+%28-%28-8%29%2B-sqrt%28%28-8%29%5E2-4%281%29%28-16%29%29%29%2F2%281%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Simplify:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+%288%2B-sqrt%2864-%28-64%29%29%29%2F2 ALIGN=MIDDLE  ALT=\"r+=+%288%2B-sqrt%2864-%28-64%29%29%29%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+%288%2B-sqrt%28128%29%29%2F2 ALIGN=MIDDLE  ALT=\"r+=+%288%2B-sqrt%28128%29%29%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+4%2B4sqrt%282%29 ALIGN=MIDDLE  ALT=\"r+=+4%2B4sqrt%282%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > or <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+4-4sqrt%282%29 ALIGN=MIDDLE  ALT=\"r+=+4-4sqrt%282%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > or approximately...<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight_green%28r+=+9.65685%29 ALIGN=MIDDLE  ALT=\"highlight_green%28r+=+9.65685%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > or <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cross%28r+=+-1.65685%29 ALIGN=MIDDLE  ALT=\"cross%28r+=+-1.65685%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Discard the negative solution as the radius can only be a positive value!<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );