document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1121388>Question 1121388</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Show that A(1,1),B(4,1),C(3,-2) and D(0,-2) are the vertices of a parallelogram </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #737289 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=737289\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "Sides AB and CD are both horizontal, because the y coordinates are the same in each pair.  So AB and CD are parallel.<br><BR>\n" );
document.write( "Find the slopes of AD and BC; if they are the same, then the vertices form a parallelogram because you have two pairs of parallel opposite sides. </SPAN>\n" );
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