document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=265609>Question 265609</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The vertices of quadrilateral ABCD are A(4,0), B(13,3), C(12,6) and D(3,3).\r<BR>\n" );
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document.write( "How do I show ABCD is a rectangle? (I've already proved it to be a quadrilateral.) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #195266 by </B><A HREF=/tutors/aboutme.mpl?userid=dabanfield><B>dabanfield(803)</B></A><img src=\"/images/stars/stars-11.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=dabanfield><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=195266\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Show that the lines AB and CD are parallel (same slopes) and that the lines BC and AD are also parallel (same slopes). Then show that the line AB is perpendicular to BC (slopes are negative reciprocals) and that AD is perpendiucular to CD (slopes are negative reciprocals). \r<BR>\n" );
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document.write( "Then show that the distance from A to B is equal to the distance from C to D and that the distance from BC is equal to the distance from AD.  </SPAN>\n" );
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