document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=818385>Question 818385</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Given the coordinates of the vertices for<BR>\n" );
document.write( "parallelogram ABCD, how can you use the<BR>\n" );
document.write( "coordinates to show that ABCD is a rectangle? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #492496 by </B><A HREF=/tutors/aboutme.mpl?userid=richwmiller><B>richwmiller(17219)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richwmiller><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=richwmiller><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=492496\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> show that the corners are right angles is the best<BR>\n" );
document.write( "the lines should all be perpendicular.<BR>\n" );
document.write( "show the slopes multiply to -1\r<BR>\n" );
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document.write( "Before you do that you might want to show that the opposite sides are equal length if it is easy to do. <BR>\n" );
document.write( "If they aren't equal length then you are done </SPAN>\n" );
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