document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=281561>Question 281561</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A triangle has vertices K(-2,2), L(1,5) and M (3,-3). Verify that the triangle has a right angle<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 #227016 by </B><A HREF=/tutors/aboutme.mpl?userid=J2R2R><B>J2R2R(94)</B></A><img src=\"/images/stars/stars-08.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=J2R2R><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=J2R2R><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=227016\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A triangle has vertices K(-2,2), L(1,5) and M (3,-3). Verify that the triangle has a right angle.\r<BR>\n" );
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document.write( "Gradient of KL = (5-2)/(1--2) = 3/3 = 1\r<BR>\n" );
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document.write( "Gradient of LM = (-3-5)/(3-1) = (-8)/2 = -4\r<BR>\n" );
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document.write( "Gradient of MK = (2--3)/(-2-3) = 5/(-5) = -1\r<BR>\n" );
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document.write( "A right angle means that the product of the gradients of the lines making the right angle is -1.\r<BR>\n" );
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document.write( "Here we see KL and MK are at right angles since the product of their gradients is -1. Thus K must be a right angle. </SPAN>\n" );
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