document.write( "Question 1067844: show that points (1,2,3);(-1,-2,-1);(2,3,2) and (4,7,6) are vertices of parallelogram but it is not a rectangle. \n" ); document.write( "

Algebra.Com's Answer #683056 by KMST(5328) $\"\"$ $\"About$

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\n" ); document.write( "The vector from $\"B\"$ to $\"A\"$ is
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.
\n" ); document.write( "The vector from $\"C\"$ to $\"D\"$ is the same:
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,
\n" ); document.write( "So AB and DC area parallel,
\n" ); document.write( "going in the same direction,
\n" ); document.write( "and with the same length,
\n" ); document.write( "That makes ABCD a parallelogram.
\n" ); document.write( "To be a rectangle the diagonals AC and BD should have the same length.
\n" ); document.write( "However, their length squared are different:
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and
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