Mat(h)s in orienteering

The first picture describes the runnability of the forest(IOF.org) But which is the best route choice? I have always been wondering what would be the fastest direction to run in when heading towards a path with runnability of 100%. Not Mats Troeng or Mats Haldin will give the answer, but some simple Mathematics.
It wasn't that difficult to calculate. Pythagoras helped me a little bit.
The results were a little bit surprising to me.(0° is straight towards the path)

The best angle to run towards a road when running in white forest (90%) is about 60°. When runnability is 70% the best angle is 45 degrees. When the speed is reduced to 20% the best angle still remains 10°.

Will this affect the way of orienteering ... do you trust more on your orienteering instinct than on Pythagoras?