document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=399062>Question 399062</A>: <I><SPAN STYLE=\"word-break: break-all;\"> if i am doing indirect proofs could you please explain it to me how to do them because my teacher stinks, she just taught us this yesterday and now we have a test on it, for example,\r<BR>\n" );
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document.write( "write an indirect proof, <BR>\n" );
document.write( "given:trapezoid ABCD with segment AB parallel to segment DC <BR>\n" );
document.write( "prove: angle C and angle D are not both right angles </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #282741 by </B><A HREF=/tutors/aboutme.mpl?userid=richard1234><B>richard1234(7193)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richard1234><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=richard1234><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=282741\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> You assume that angles C and D equal 90 degrees, then show that a contradiction occurs. In this case, since angle B + angle C = 180, and angle A + angle D = 180 (due to the fact that AB and CD are parallel), then all four angles are equal to 90, and you have a rectangle, which by definition, is not a trapezoid. </SPAN>\n" );
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