document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=384731>Question 384731</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If A(1,2), B(5,6) and C(-2,-5) are the vertices of a triangle ABC, find the area of triangle ABC. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #272358 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=272358\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If A(1,2), B(5,6) and C(-2,-5) are the vertices of a triangle ABC, find the area of triangle ABC.<BR>\n" );
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document.write( "There's a little known method that works for all polygons, regardless of the number of sides.<BR>\n" );
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document.write( "List the points in columns, repeat the 1st point<BR>\n" );
document.write( "A B C  A<BR>\n" );
document.write( "1 5 -2 1<BR>\n" );
document.write( "2 6 -5 1<BR>\n" );
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document.write( "Starting at the left, add the diagonal products \"upward\" and \"downward\"<BR>\n" );
document.write( "Upward: 2*5 + 6*-2 + -5*1 = 10 - 12 - 5 = -7<BR>\n" );
document.write( "Downward: 1*6 + 5*-5 + -2*1 = 6 - 25 - 2 = -21<BR>\n" );
document.write( "The difference = 14<BR>\n" );
document.write( "The area is 1/2 that, = 7 sq units<BR>\n" );
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