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document.write( "The first two tutors did it by slopes and showing they are points on the same\r\n" );
document.write( "line. Those are valid methods, but the method asked for here is how to do it\r\n" );
document.write( "by addition of line segments.\r\n" );
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\r\n" );
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document.write( "We use the distance formula to find the length of the line segment from a(-3,0)\r\n" );
document.write( "to b(-1,-1)\r\n" );
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document.write( "
\r\n" );
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document.write( "Now we use the distance formula also to find the length of the line segment\r\n" );
document.write( "from the point b(-1,-1) to c(5,-4)\r\n" );
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document.write( "
\r\n" );
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document.write( "Now we find the length of the line segment from a(-3,0) to c(5,-4) to see if the\r\n" );
document.write( "sum of those two segments equals to this total length.\r\n" );
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document.write( "
\r\n" );
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document.write( "And we see that the sum of the two shorter line segments equal to the whole\r\n" );
document.write( "longest line segment:\r\n" );
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document.write( "
\r\n" );
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document.write( "That proves that all three points lie on the same line.\r\n" );
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document.write( "Edwin
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document.write( "![\"\"](\"/images/stars/stars-13.gif\")
