document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=844597>Question 844597</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A rectangle is a parallelogram \r<BR>\n" );
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document.write( "Is it always, sometimes, or never true ? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #508865 by </B><A HREF=/tutors/aboutme.mpl?userid=KMST><B>KMST(5328)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=KMST><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=KMST><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=508865\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> It is always true.<BR>\n" );
document.write( "A parallelogram is a quadrilateral where opposite sides are parallel.<BR>\n" );
document.write( "So a quadrilateral ABCD is a parallelogram if and only if AB is parallel to DC,<BR>\n" );
document.write( "and BC is parallel to AD.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=drawing%28300%2C200%2C-1%2C5%2C-1%2C3%2C%0D%0Aline%280%2C0%2C1%2C2%29%2Cline%280%2C0%2C3%2C0%29%2C%0D%0Aline%283%2C0%2C4%2C2%29%2Cline%281%2C2%2C4%2C2%29%2C%0D%0Alocate%280.8%2C2.2%2CA%29%2Clocate%284%2C2.2%2CB%29%2C%0D%0Alocate%283.1%2C0.2%2CC%29%2Clocate%28-0.2%2C0.2%2CD%29%0D%0A%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The angles between side AB and adjacent sides AD and BC are supplementary (their measures add up to <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=180%5Eo ALIGN=MIDDLE  ALT=\"180%5Eo\"   DISABLED_style= \"max-width:90%; height:auto;\" > .<BR>\n" );
document.write( "The angles between side CD and adjacent sides AD and BC are supplementary.<BR>\n" );
document.write( "The angles at opposite vertices are congruent.<BR>\n" );
document.write( "There are only two interior angle measures for a parallelogram, and those two angle measures add up <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=180%5Eo ALIGN=MIDDLE  ALT=\"180%5Eo\"   DISABLED_style= \"max-width:90%; height:auto;\" > .<BR>\n" );
document.write( "In the figure above,<BR>\n" );
document.write( "the angles at A and C are a pair congruent angles (they have the same measure);<BR>\n" );
document.write( "the angles at B and D are another pair of congruent angles,<BR>\n" );
document.write( "and any angle of one of those pairs is supplementary to any angle from the other pair.<BR>\n" );
document.write( "If all the angles in a parallelogram have the same measure, they all measure <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=90%5Eo ALIGN=MIDDLE  ALT=\"90%5Eo\"   DISABLED_style= \"max-width:90%; height:auto;\" > , and the parallelogram is a rectangle, which is a special kind of parallelogram. </SPAN>\n" );
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