Suggest you use Google Earth;use the little info box,top left ,press view,then press `grid`,and all the latitudes/longitudes should appear;next box is `tools. select `ruler`.
Now pick a point ,say anywhere in California,and draw a line around the World to London(England).It should go across Canada,Greenland to England in a curve/Great circle.Note it will also give you your initial heading,approx 035 *.Now draw another line from about 1/3 of the track ,(HudsonsBay area) parallel to the main track to the East coast of Greenland.IT should be about 056* appx. at the start of that line.Now draw the final track ,parallel to the main track to London.the initial heading will be about 097*.So ,you have travelled about 110* of Longitude,and the heading has changed about 60*....
If you travel E OR W around the Equator,your heading will not change(much)...