document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1004275>Question 1004275</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The area of a circle is directly proportional to the square of its radius. The area of a circle whose diameter is 40 cm is 1256 sq cm. What is the area of a circle whose diameter is 20 cm? 10 cm? 12 cm? 30 cm? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #620781 by </B><A HREF=/tutors/aboutme.mpl?userid=Cromlix><B>Cromlix(4381)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Cromlix><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=Cromlix><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=620781\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Hi there,<BR>\n" );
document.write( "The area of a circle is directly <BR>\n" );
document.write( "proportional to the square of its radius.<BR>\n" );
document.write( "A = kr^2<BR>\n" );
document.write( "Where k = constant of proportionality<BR>\n" );
document.write( "A = kr^2<BR>\n" );
document.write( "1256 = k20^2<BR>\n" );
document.write( "k = 1256/400<BR>\n" );
document.write( "k = 3.14<BR>\n" );
document.write( "Formula:<BR>\n" );
document.write( "A = 3.14r^2<BR>\n" );
document.write( "Problem:<BR>\n" );
document.write( "A = 3.14 x 10^2<BR>\n" );
document.write( "A = 3.14 x 100<BR>\n" );
document.write( "A = 314 sq cm.<BR>\n" );
document.write( "Hope this helps :-) </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );