document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=141814>Question 141814</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0395937779/algebrahomeworkh></A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> how do you find the area of a regular pentagon with radius 10cm? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #103361 by </B><A HREF=/tutors/aboutme.mpl?userid=edjones><B>edjones(8007)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=edjones><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=edjones><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=103361\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> r=10, s=side length, n=number of sides, A=area<BR>\n" );
document.write( "For any regular polygon: r=s/(2sin(pi/n)) using radians.<BR>\n" );
document.write( "10=s/(2sin(pi/5))<BR>\n" );
document.write( "10=s/1.17557...<BR>\n" );
document.write( "s=11.76...<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Heron's Law:<BR>\n" );
document.write( "Let a=10, b=10, c=11.76<BR>\n" );
document.write( "s=(a+b+c)/2 Don't confuse this s with the s above which is now c. This is a new s.<BR>\n" );
document.write( "=(10+10+11.76)/2<BR>\n" );
document.write( "=15.88...<BR>\n" );
document.write( "A=sqrt(s(s-a)(s-b)(s-c)) Area of the triangle<BR>\n" );
document.write( "=sqrt(15.88(15.88-10)(15.88-10)(15.88-11.76))<BR>\n" );
document.write( "=47.56<BR>\n" );
document.write( "47.56*5=237.8 cm^2 Area of the pentagon.<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Ed </SPAN>\n" );
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