Post 345 is plotting problem. You need a 'Geometry box' for solving it.
Referring to you diagram :
480 nm on 110E = 8 deg
So A is at 82N 110E
Keep one end of the divider on the North pole and the other at point A. Measure that distance on the scale which is say X cm.
If X cm = 480 nm then find how much it will be for 300 nm say Y cm.
Now keep the divider along 154(AR) such that one end is on point A. The other end which is Y cm from A will be the a/c position say point B. (300 nm along grid track 154)
Join B and N (north pole)
Measure that distance in cm with the divider and find how many nm it is say Z nm. 90 - Z/60 = Latitude of new postion.
Keep the protractor at N and measure angle PNB and subtract that value from 110E and that will be the Longitude of the new position.