document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=285533>Question 285533</A>: <I><SPAN STYLE=\"word-break: break-all;\"> What is the diameter (in cm) of the circle whose area (in cm2) and circumference (in cm) have the same numerical value?\r<BR>\n" );
document.write( "\n" );
document.write( "A. 1 cm B. 2 cm C. 3 cm D. &#960;  cm E. 4 cm </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #206948 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=206948\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Area = pi*r^2<BR>\n" );
document.write( "Circumference = 2*pi*r\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "If area = circumference, then:\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "pi*r^2 = 2*pi*r\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Divide both sides of this equation by pi to get:\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "r^2 = 2*r\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Divide both sides of this equation by r to get:\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "r = 2\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Diameter = 2*r so D = 4\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Your answer is that the area and the circumference of a circle are equal when the diameter is equal to 4.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "That would be selection E (4 cm).\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Take half that diameter to get a radius of 2.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Circumference = 2*pi*r = 4*pi\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Area = pi*r^2 = pi*2^2 = pi*4 = 4*pi\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Area and Circumference are equal when the diameter is 4 cm.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );