Question 136578
To find this answer you need to know 2 things.
1) how to calculate the slope of a line given two points on that line
2) the relationship between the slopes of lines that are perpendicular to each other.

To fine the slope given two points:
{{{m = (y[2]-y[1])/(x[2]-x[1])}}}

You have the two points, you do the math

To find the slope of a line that is perpendicular to a line with a given slope, you need to know that the slopes of those lines result in a product of {{{-1}}}

{{{m*m[p] = -1 }}}  where m[p] is the slope of the perpendicular line

That ought to get you there!