How do you find the slope of the line that is perpendicular to the line through (1, 9) and (10, 3 and 1/2)?

1 Answer
David Drayer · Stefan V.
Aug 5, 2016

#18/11#

Find the slope of the line by dividing the change in the y values by the change in the x values. Then take the negative inverse of the slope of the line.

Explanation:

The slope equals the change in #y# divided by the change in #x#, so

#y = 9 - 3 1/2 = 5 1/2#

#x = 1 - 10 = -9#

#"slope" = (5 1/2)/(-9)#

Multiply #5 1/2 xx 2 = 11#, then multiply #-9 xx 2 = - 18#, so the slope of the line is

#"slope" = - 11/18#

The negative inverse is #+ 18/11#

So the slope of the line that is perpendicular to the line is #+ 18/11#

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