document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=397109>Question 397109</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I'm so lost on this question! Please help!!\r<BR>\n" );
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document.write( "\" use coordinate geometery to prove that the diagonals of a square are perpendicular\" </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #281514 by </B><A HREF=/tutors/aboutme.mpl?userid=robertb><B>robertb(5830)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=robertb><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=robertb><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=281514\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let A(0,0), B(a,0), C(0,a), and D(a,a) be the vertices of the square.<BR>\n" );
document.write( "Then line AD has slope <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28a+-+0%29%2F%28a+-+0%29+=+1 ALIGN=MIDDLE  ALT=\"%28a+-+0%29%2F%28a+-+0%29+=+1\"   DISABLED_style= \"max-width:90%; height:auto;\" >, while<BR>\n" );
document.write( "line BC has slope <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%280-a%29%2F%28a-0%29+=+-a%2Fa+=+-1 ALIGN=MIDDLE  ALT=\"%280-a%29%2F%28a-0%29+=+-a%2Fa+=+-1\"   DISABLED_style= \"max-width:90%; height:auto;\" >.<BR>\n" );
document.write( "Hence the slopes are negative reciprocals of each other, and the lines AD and BC are perpendicular. </SPAN>\n" );
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