Sneech
Answer
18 degrees heading change required to the left.
All based on 1 in 60 rule and similar triangles
1 degree track error over 60units of distance will place you 1 unit of distance off track.
Best to DRAW this to follow it
So you go from 4 nm left of track to 2 nm right of track over 30nm.
Assume you were on track at the start(and not 4 nm left of it) that same heading would place you 6nm (4+2) right of track after 30 nm on the same heading. Multiply both by 2 to get the magic 60 units of distance and you have 12 units right of track and are therefore tracking 12 degrees right of the desired track.
You are 20 nm from destination and 2nm right of track and we know that at this point we are heading 12 degrees right of the heading we should have started with, lets see 3 X 20 = 60 so 3 X 2 = 6 degrees 12+6 =18 degrees
Notice how all the distances are easy multiples of 60?
I hope all this waffle helps you do a search on google for 1 in 60 rule theres heaps out there that explain it better than I do
Wunper
