Question 82860
First lets find the slope of the line going through (8, 9) and (4, 8)


*[invoke slope 8, 9, 4, 8]


Remember, perpendicular slopes are always the negative reciprocal of each other. In other words we have


{{{m[p]=-1/m}}} where {{{m[p]}}} is the perpendicular slope


so plug in the slope we solved for to find the perpendicular slope:


{{{m[p]=-1/(1/4)=-(1/1)*(4/1)=4}}} Plug in m=2


So the perpendicular slope is {{{-4}}}