document.write( "Question 1097523: How do you know if a line is perpindicualar \n" ); document.write( "

Algebra.Com's Answer #711954 by Alan3354(69443) $\"\"$ $\"About$

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How do you know if a line is perpindicualar [sic]
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\n" ); document.write( "A line has to be perpendicular to something, often another line.
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\n" ); document.write( "If they're in the x-y plane, their slopes are negative inverses, eg,
\n" ); document.write( "2 and -1/2.
\n" ); document.write( "If the angles at the intersection = 90 degs, they're perpendicular.
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