Karlee has been spending the day exploring the woods near her house. It was getting late and Karlee needed to get back home. The quickest way home for Karlee is to follow the bike path on the other side of the woods, In her coordinate map, Karlee determined that her position was (-4,1) and that the bike was located along the line -x-2y+4=0. Determine the shortest distance that Karlee needs to travel to reach the bike path from her current position.

There is a formula for this. 
Given a line ax+by+c=0 and a point, the shortest distance between them is: