Calculating the perpendicular distance from a point to a line in 2D is useful, when you want to find out what the nearest (i.e. closest or shortest) distance is from that point, to the line. Here is the formula:

```
given lineStartPoint { X, Y } -> the line's start point in 2D space
given lineEndPoint { X, Y } -> the line's end point in 2D space
given point { X, Y } -> the point in 2D space whose nearest distance should be calculated
neartestDistance =
Abs(
(lineEndPoint.Y - lineStartPoint.Y) * point.X
- (lineEndPoint.X - lineStartPoint.X) * point.Y
+ lineEndPoint.X * lineStartPoint.Y
- lineEndPoint.Y * lineStartPoint.X
)
/
Sqrt(
(lineEndPoint.Y - lineStartPoint.Y)
* (lineEndPoint.Y - lineStartPoint.Y)
+ (lineEndPoint.X - lineStartPoint.X)
* (lineEndPoint.X - lineStartPoint.X)
)
```