document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=335072>Question 335072</A>: <I><SPAN STYLE=\"word-break: break-all;\"> how do you find a value of a variable? there's a pentagon with numbers of degrees on only 4 sides. the fifth is a variable. how do you solve this problem? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #240201 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=240201\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A pentagon has 5 sides.\r<BR>\n" );
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document.write( "It also has 5 angles.\r<BR>\n" );
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document.write( "The sum of the interior angles of any polygon is given by the equation:\r<BR>\n" );
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document.write( "s(a) = (n-2) * 180\r<BR>\n" );
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document.write( "a means interior angles of the polygon.<BR>\n" );
document.write( "n means number of sides of the polygon.<BR>\n" );
document.write( "s (a) means sum of the interior angles of the polygon.\r<BR>\n" );
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document.write( "for a triangle, that would become:\r<BR>\n" );
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document.write( "s(a) = (3-2) * 180 = 1 * 180 = 180 degrees.\r<BR>\n" );
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document.write( "for a rectangle, that would become:\r<BR>\n" );
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document.write( "s(a) = (4-2) * 180 = 2 * 180 = 360 degrees.\r<BR>\n" );
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document.write( "for a pentagon, that would become:\r<BR>\n" );
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document.write( "s(a) = (5-2) * 180 = 3 * 180 = 540 degrees.\r<BR>\n" );
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document.write( "Since you know 4 of the angles, it's a simple matter to find the measure of the 5th angle.\r<BR>\n" );
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document.write( "You simply subtract the sum of the 4 angles from 540 to get the 5th angle.\r<BR>\n" );
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document.write( "If you look at a pentagon from a geometric perspective, you can see that it forms 5 separate triangles from the center of the pentagon to the sides of the pentagon.\r<BR>\n" );
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document.write( "Just draw a dot in the center of the pentagon and then draw lines from the center of pentagon to each corner of the pentagon to see that there are 5 triangles formed.\r<BR>\n" );
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document.write( "Since the sum of the angles of a triangle is 180 degrees, this makes a total of 5 * 180 = 900 degrees.\r<BR>\n" );
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document.write( "Since the sum of the central angles of the pentagon = 360 degrees, you subtract this from 900 to get 900 - 360 = 540 degrees.\r<BR>\n" );
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document.write( "That becomes the sum of the internal angles of the polygon, which are the angles formed by the corners of the pentagon.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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