document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=33017>Question 33017</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A(-1;4):B(2;3): C(0;-3): D(-3;-2) <BR>\n" );
document.write( "these points on a graph make a rectangle...specify...<BR>\n" );
document.write( "what is the equation for the diagonales d1 and d2 of the rectangle?\r<BR>\n" );
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document.write( "what is the equation of the medianes m1 and m2 of the rectangle?\r<BR>\n" );
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document.write( "what is the area of this rectangle? </SPAN>\n" );
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document.write( "A(-1;4):B(2;3): C(0;-3): D(-3;-2)\r<BR>\n" );
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document.write( " Vector  AB = B-A = (3, -1) = 3i - j<BR>\n" );
document.write( " DC = C - D = (-3, -1) = 3 i - j,<BR>\n" );
document.write( " BC = C - B = (-2, -6) = -2 i - 6j<BR>\n" );
document.write( " DA = D -A =  (-2, -6) = -2 i - 6j<BR>\n" );
document.write( " We see that AB = CD & BC = DA so AB // CD and BC // DA<BR>\n" );
document.write( " Also, the dot product AB. DA = (3i-j).(2i+6j) = 6-6 =0<BR>\n" );
document.write( " Hence, ABCD is a rectangle\r<BR>\n" );
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document.write( " Use the basic two points formula (don't ask me!) to get the equation for<BR>\n" );
document.write( " diagonals AC and BD. (d1 & d2)<BR>\n" );
document.write( " Also the four midpoitns are (1/2, 1/2), (1,0), (-1/2, -1/2) and (-1,1)<BR>\n" );
document.write( " so you can get the eqatioins for m1 & m2.<BR>\n" );
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document.write( " The area of ABCD is  equal to the magnitude of the direct product<BR>\n" );
document.write( " AB x  AD = (3i-j) x (2i - 6j) = 2 k - 18 k = -16 k.\r<BR>\n" );
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document.write( " So area = 16.\r<BR>\n" );
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document.write( " Kenny\r<BR>\n" );
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document.write( " </SPAN>\n" );
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