<PRE><B>Question 252782</B>
The slope of the established road is {{{m=(13-9)/(2-4)=4/-2=-2}}}.


The slope of the perpendicular road is the negative reciprocal = 1/2.  If it passes through the point (4,9), then you would probably want to use the point slope formula:
y-9=1/2(x-4)
y-9=1/2x-2


Add +9 to each side:
y=1/2x-2+9
y=1/2x+7


Dr. Robert J. Rapalje, Retired
Seminole State College of Florida</PRE>