document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=408883>Question 408883</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If you are given the coordinates of the vertices, how do you prove that it is 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 #287955 by </B><A HREF=/tutors/aboutme.mpl?userid=MathLover1><B>MathLover1(20850)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=MathLover1><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=MathLover1><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=287955\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> \r<BR>\n" );
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document.write( "A common type of proof involves proving that a quadrilateral is a parallelogram. If any of the 5 conditions below are met, then the quadrilateral must be a parallelogram. \r<BR>\n" );
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document.write( "    1) If a quadrilateral has one pair of sides that are both parallel and congruent, then the quadrilateral is a parallelogram.\r<BR>\n" );
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document.write( "   2) If a the opposite sides of a quadrilateral are congruent, then then quadrilateral is a parallelogram.\r<BR>\n" );
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document.write( "    3) Opposites sides are parallel.\r<BR>\n" );
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document.write( "    4) Opposite angles are congruent\r<BR>\n" );
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document.write( "  5) Diagonals bisect each other.\r<BR>\n" );
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document.write( "so, plot your vertices and see if they meet any of criteria above\r<BR>\n" );
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