document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=587246>Question 587246</A>: <I><SPAN STYLE=\"word-break: break-all;\"> What is the area of the quadrilateral with vertices A(0,2), B(15,10), C (15,2), & D(0,-18)? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #374038 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=374038\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> What is the area of the quadrilateral with vertices A(0,2), B(15,10), C (15,2), & D(0,-18)?<BR>\n" );
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document.write( "Make a matrix, 2 by P, the number of points, repeat the first point.<BR>\n" );
document.write( "A...B...C...D...A<BR>\n" );
document.write( "0..15..15...0...0<BR>\n" );
document.write( "2..10...2..-18..2<BR>\n" );
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document.write( "Add the diagonal products starting at the upper left:<BR>\n" );
document.write( "0 + 30 - 270 + 0 = -240<BR>\n" );
document.write( "Add the diagonal products starting at the lower left:<BR>\n" );
document.write( "30 + 150 + 0 + 0 = 180<BR>\n" );
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document.write( "The area is 1/2 the ABS of the difference<BR>\n" );
document.write( "|-240 - 180| = 420<BR>\n" );
document.write( "Area = 210 sq units.<BR>\n" );
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document.write( "It works for all polygons, any number of sides.<BR>\n" );
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