There are many ways to write the equation of the line representing the road. Under the circumstances, it may work well to use this form.
∆y·(x -x1) - ∆x·(y -y1) = 0
where ∆x = x2 -x1, and ∆y = y2 -y1.
Substituting the given numbers, this is
(375-145)(x -150) -(550-150)(y -145) = 0
230(x -150) -400(y -145) = 0
Dividing by 10 and eliminating parentheses, this becomes
23x -40y +2350 = 0
This general-form equation is very useful for finding the distance from a point to a line. For general form line ax+by+c=0, the distance to the line from point (x,y) is ...
d = |ax +by +c|/√(a²+b²)
Using this formula and the given point, the shortest distance to the road is ...
d = |23×220 -40×430 +2350|√(23²+40²)
d = 9790/√2129
d ≈ 212.175
The shortest distance from your location to the road is about 212.2 miles.
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A geometry program comes to the same conclusion.