document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=289972>Question 289972</A>: <I><SPAN STYLE=\"word-break: break-all;\"> how do you find the area of an octagon with a radius of 10?? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #209916 by </B><A HREF=/tutors/aboutme.mpl?userid=CharlesG2><B>CharlesG2(834)</B></A><img src=\"/images/stars/stars-11.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=CharlesG2><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=209916\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> how do you find the area of an octagon with a radius of 10?\r<BR>\n" );
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document.write( "A area = 1/2 * n * r^2 * sin((2pi)/n)<BR>\n" );
document.write( "this is the area of 8 triangles arranged in a circle<BR>\n" );
document.write( "area of 1 triangle = 1/2 * r^2 * sin(2pi/8)<BR>\n" );
document.write( "area of 1 triangle = 1/2 * r^2 * sin(pi/4) <BR>\n" );
document.write( "(r^2 = 100)<BR>\n" );
document.write( "(sin pi/4 = sin (45 deg.))<BR>\n" );
document.write( "area of 1 triangle = 1/2 * r^2 * sqrt(2)/2) = sqrt(2)/4 * 100<BR>\n" );
document.write( "area of 1 triangle = 25sqrt(2)<BR>\n" );
document.write( "total area = 8 * 25 * sqrt(2)= 200sqrt(2)\r<BR>\n" );
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