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document.write( "Use the slope formula to show that all four sides are perpendicular.\r\n" );
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document.write( "To show that the line from (-1,0) to (2,3) is perpendicular\r\n" );
document.write( "to the the line segment from (2,3) to (5,0),\r\n" );
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document.write( "1. find the slope of the line segment from \r\n" );
document.write( "(-1,0) to (2,3):\r\n" );
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document.write( "Use the slope formula:\r\n" );
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document.write( "where (x1,y1) = (-1,0)\r\n" );
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document.write( "and where (x2,y2) = (2,3)\r\n" );
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document.write( "2. find the slope of the line segment from \r\n" );
document.write( "(2,3) to (5,0):\r\n" );
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document.write( "Use the slope formula:\r\n" );
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document.write( "

\r\n" );
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document.write( "this time where (x1,y1) = (2,3)\r\n" );
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document.write( "and where (x2,y2) = (5,0)\r\n" );
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document.write( "3. Point out that their slopes 1 and -1, are \r\n" );
document.write( "opposite-signed reciprocals, or what is the\r\n" );
document.write( "same thing, their product (1)(-1) is -1. That\r\n" );
document.write( "proves that they are perpendicular and that the\r\n" );
document.write( "angle between them is a right angle.\r\n" );
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document.write( "4. Find the length of the line segment from \r\n" );
document.write( "(-1,0) to (2,3):\r\n" );
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document.write( "Use the distance formula:\r\n" );
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document.write( "

\r\n" );
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document.write( "where (x1,y1) = (-1,0)\r\n" );
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document.write( "and where (x2,y2) = (2,3)\r\n" );
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document.write( "5. Find the length of the line segment from \r\n" );
document.write( "(2,3) to (5,0):\r\n" );
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document.write( "Use the distance formula:\r\n" );
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document.write( "

\r\n" );
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document.write( "this time where (x1,y1) = (2,3)\r\n" );
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document.write( "and where (x2,y2) = (5,0)\r\n" );
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document.write( "

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document.write( "

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document.write( "

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document.write( "6. Point out that the two line segments are equal\r\n" );
document.write( "in length.\r\n" );
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document.write( "Now, using the same method, finish by showing that\r\n" );
document.write( "the slope of the line segment from (5,0) to (2,-3)\r\n" );
document.write( "is perpendicular to the line segment from (2,3) to\r\n" );
document.write( "(5,0). Then show that those line segments are\r\n" );
document.write( "equal in length. \r\n" );
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document.write( "Then show that the slope of the line segment from \r\n" );
document.write( "(5,0) to (2,-3) is perpendicular to the line segment \r\n" );
document.write( "from (2,-3) to (-1,0). Then show that those line \r\n" );
document.write( "segments are equal in length.\r\n" );
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document.write( "Then point out that the line segment from (2,-3) to\r\n" );
document.write( "(-1,0) is perpendicular to the line segment from\r\n" );
document.write( "(-1,0) to (2,3), and that is has the same length.\r\n" );
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document.write( "You finish.\r\n" );
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document.write( "Edwin
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document.write( "