document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=912739>Question 912739</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me solve this proof:\r<BR>\n" );
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document.write( "Prove that if a line is drawn through the vertex of an isosceles triangle parallel to the base, it bisects the exterior angle at the vertex.\r<BR>\n" );
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document.write( "I have drawn the picture as the question states, but am not sure how to prove that the line bisects the exterior angle with steps using a proof. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #554063 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><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=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=554063\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> \r<BR>\n" );
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document.write( "Let ABC be the triangle\r<BR>\n" );
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document.write( "AE is drawn parallel to BC\r<BR>\n" );
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document.write( "CAF is the external angle\r<BR>\n" );
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document.write( "To prove AE bisects CAF\r<BR>\n" );
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document.write( "AE is parallel to BC and AC is the transversal\r<BR>\n" );
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document.write( "So angle CAE = ACB ( alternate angle test)\r<BR>\n" );
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document.write( "AE is parallel to BC and Bf is the transversal<BR>\n" );
document.write( "so EAF = ABC ( corresponding angles test)\r<BR>\n" );
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document.write( "But ABC = ACB ( isosceles triangle)\r<BR>\n" );
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document.write( "therefore EAF = CAE </SPAN>\n" );
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