Set up a ratio:
1/50 = x/480
Cross multiply:
50x = 480
Divide both sides by 50:
X = 9.6
The distance on the map is 9.6 cm
You start by finding the slope : y2 - y1 / x2 - x1
2 - 8 / 4 - (-16)
- 6 / 20
m = - 3 / 10
Point slope form : y - y1 = m( x- x1 )
You can pick either of the coordinates and substitute them in
POINT SLOPE FORM EQUATION : y - 8 = -3/10 ( x + 16 )
One equation for this would be

We start by finding the slope between the two points:

A line parallel to this one will have the same slope. We will use point-slope form to write our equation: