document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1180960>Question 1180960</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In a circle with diameter of 20 cm, a regular five-pointed star touching its circumference is inscribed. Find the area of the star. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #810947 by </B><A HREF=/tutors/aboutme.mpl?userid=MathLover1><B>MathLover1(20849)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=MathLover1><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=MathLover1><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=810947\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> \r<BR>\n" );
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document.write( "there are <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5 ALIGN=MIDDLE  ALT=\"5\"   DISABLED_style= \"max-width:90%; height:auto;\" > central angles\r<BR>\n" );
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document.write( "each angle is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=360%2F5+=+72 ALIGN=MIDDLE  ALT=\"360%2F5+=+72\"   DISABLED_style= \"max-width:90%; height:auto;\" > degrees\r<BR>\n" );
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document.write( "label a point of the star on the circumference A, center of the circle O and the intersection of the side of A and the side of the point of the star adjacent to A going clockwise B.\r<BR>\n" );
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document.write( "angle AOB is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=72%2F2+=+36+ ALIGN=MIDDLE  ALT=\"72%2F2+=+36+\"   DISABLED_style= \"max-width:90%; height:auto;\" >degrees and angle AOB is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=36%2F2+=+18 ALIGN=MIDDLE  ALT=\"36%2F2+=+18\"   DISABLED_style= \"max-width:90%; height:auto;\" > degrees\r<BR>\n" );
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document.write( "for triangle AOB, we have\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=36+%2B18+%2Bbeta+=+180 ALIGN=MIDDLE  ALT=\"36+%2B18+%2Bbeta+=+180\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=beta+=+180+-36+-18+=+126 ALIGN=MIDDLE  ALT=\"beta+=+180+-36+-18+=+126\"   DISABLED_style= \"max-width:90%; height:auto;\" > degrees\r<BR>\n" );
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document.write( "radius of circle = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20%2F2+=+10+ ALIGN=MIDDLE  ALT=\"20%2F2+=+10+\"   DISABLED_style= \"max-width:90%; height:auto;\" >cm\r<BR>\n" );
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document.write( "Now use the law of sines \r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28OB%2Fsin%2818%29%29+=+%2810%2Fsin%28126%29%29 ALIGN=MIDDLE  ALT=\"%28OB%2Fsin%2818%29%29+=+%2810%2Fsin%28126%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=OB+=+10%2Asin%2818%29%2Fsin%28126%29 ALIGN=MIDDLE  ALT=\"OB+=+10%2Asin%2818%29%2Fsin%28126%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=OB+=+3.8197 ALIGN=MIDDLE  ALT=\"OB+=+3.8197\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Area of triangle<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+AOB+=+%281%2F2%29%2A3.8197%2A10%2Asin%2836%29+=+11.2258 ALIGN=MIDDLE  ALT=\"+AOB+=+%281%2F2%29%2A3.8197%2A10%2Asin%2836%29+=+11.2258\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Area of the five pointed star = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=10%2A11.2258+=+112.258cm%5E2 ALIGN=MIDDLE  ALT=\"10%2A11.2258+=+112.258cm%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > \r<BR>\n" );
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document.write( " </SPAN>\n" );
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