document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=30714>Question 30714</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Hello!  I need to prove that a quadrilateral ABCD is a trapezoid.  We are given that the two upper angles are congruent and the two lower angles are congruent.  Our hint is that we need to use the theorem that the sum of the vertex angles of a quadrilateral is 360 degrees.  Help!!!<BR>\n" );
document.write( "~Katie </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #17448 by </B><A HREF=/tutors/aboutme.mpl?userid=venugopalramana><B>venugopalramana(3286)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=venugopalramana><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.geocities.com/venugopalramana/FREE_MATHS_ASSISTANCE.html valign=middle><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=17448\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> LET ABCD BE THE QUADRILATERAL...WE ARE GIVEN<BR>\n" );
document.write( "ANGLE A = ANGLE B = X SAY.....AND<BR>\n" );
document.write( "ANGLE C = ANGLE D = Y SAY......<BR>\n" );
document.write( "SUM OF 4 ANGLES IN A QUADRILATERAL =360...SO<BR>\n" );
document.write( "X+Y+X+Y = 360<BR>\n" );
document.write( "2(X+Y)=360<BR>\n" );
document.write( "X+Y=180<BR>\n" );
document.write( "NOW SINCE AB AND CD ARE 2 LINES AND BC IS A TRANSVERSAL,WE HAVE 2 INTERIOR ANGLES <BR>\n" );
document.write( "ON THE SAME SIDE OF TRANSVERSAL..NAMELY ANGLE B =X  AND ANGLE C =Y....THEIR SUM <BR>\n" );
document.write( "X+Y = 180.....HENCE THEY SHOULD BE PARALLEL.<BR>\n" );
document.write( "SO AB IS PARALLEL TO CD...HENCE ABCD IS A TRAPEZOID.  </SPAN>\n" );
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