document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1177064>Question 1177064</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In quadrilateral ABCD, AB=BC=1,m∠B=100degrees,m∠D=130degrees, Find BD.\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #850535 by </B><A HREF=/tutors/aboutme.mpl?userid=ikleyn><B>ikleyn(52788)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ikleyn><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=ikleyn><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=850535\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> .\r<BR>\n" );
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document.write( "This problem is posed INCORRECTLY.\r<BR>\n" );
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document.write( "From the given information, we can find diagonal AC using the cosine rule formula.\r<BR>\n" );
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document.write( "But after that, from triangle ADC, we have known the angle D = 130° and the length <BR>\n" );
document.write( "of its opposite side AC.\r<BR>\n" );
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document.write( "It is NOT ENOUGH to determine other elements of the triangle ADC,<BR>\n" );
document.write( "and the vertex D may lie in any position on the arc ADC, providing <BR>\n" );
document.write( "the inscribed angle ADC, leaning on the chord AC, is 130°.\r<BR>\n" );
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document.write( "So, the point / (the vertex) D may have infinitely many described positions <BR>\n" );
document.write( "and can not be determined in a unique way.\r<BR>\n" );
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document.write( "So, the length of BD can not be determined in a unique way - it may have different values.\r<BR>\n" );
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document.write( "The given info is not enough to solve the problem correctly to the end.\r<BR>\n" );
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document.write( "Final <U>ANSWER</U>: the problem is heavily DEFECTIVE.\r<BR>\n" );
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document.write( "The \"solution\" and the answer by @CPhill both are incorrect.\r<BR>\n" );
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document.write( "They both deceive a reader.\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Regarding the post by @CPhill . . . \r<BR>\n" );
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document.write( "Keep in mind that @CPhill is a pseudonym for the Google artificial intelligence.\r<BR>\n" );
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document.write( "The artificial intelligence is like a baby now. It is in the experimental stage <BR>\n" );
document.write( "of development and can make mistakes and produce nonsense without any embarrassment.\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;It has no feeling of shame - it is shameless.\r<BR>\n" );
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document.write( "This time, again, &nbsp;it made an error.\r<BR>\n" );
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document.write( "Although the @CPhill' solutions are copy-paste &nbsp;Google &nbsp;AI solutions, &nbsp;there is one essential difference.\r<BR>\n" );
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document.write( "Every time, &nbsp;Google &nbsp;AI &nbsp;makes a note at the end of its solutions that &nbsp;Google &nbsp;AI &nbsp;is experimental<BR>\n" );
document.write( "and can make errors/mistakes.\r<BR>\n" );
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document.write( "All @CPhill' solutions are copy-paste of &nbsp;Google &nbsp;AI &nbsp;solutions, with one difference:<BR>\n" );
document.write( "@PChill never makes this notice and never says that his solutions are copy-past that of Google.<BR>\n" );
document.write( "So, &nbsp;he &nbsp;NEVER &nbsp;SAYS &nbsp;TRUTH.\r<BR>\n" );
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document.write( "Every time, &nbsp;@CPhill embarrassed to tell the truth.\r<BR>\n" );
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document.write( "But I am not embarrassing to tell the truth, &nbsp;as it is my duty at this forum.\r<BR>\n" );
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document.write( "And the last my comment.\r<BR>\n" );
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document.write( "When you obtain such posts from @CPhill, &nbsp;remember, &nbsp;that &nbsp;NOBODY &nbsp;is responsible for their correctness, <BR>\n" );
document.write( "until the specialists and experts will check and confirm their correctness.\r<BR>\n" );
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document.write( "Without it, &nbsp;their reliability is &nbsp;ZERO and their creadability is &nbsp;ZERO, &nbsp;too.\r<BR>\n" );
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