Put
away your protractor and think about what grid is - simply two sets of
perpendicular parallel lines, one set of which points to Grid North, drawn on a
piece of paper (the chart).
Any
other straight line (your course) drawn on the paper will cut each of the parallel
lines (of a set) at the same angle.
In
other words, the grid direction of your course is the same all over the chart -
so, in this case, it will be 177 degrees at both points in the question.