1st we need to know the slope of the line with the points (4, 2) and (-1, 4)
m = [tex] \frac{4 - 2}{-1 - 4} = \frac{-2}{5} [/tex]
If the segments are perpendicular, then the slopes will multiply to -1
[tex]4* \frac{-2}{5} = -\frac{8}{5} \neq -1 [/tex]
Since the product is not -1 then the lines are not perpendicular.
