# Homework Help: Can someone explain this to me

1. Sep 7, 2009

### xpack

Let speed be s

s^2 = 4^2 + 9^2

s^2 = 377

s = 19.4 mph

Ө = Tan^(-1) [ 19/4 ] = 78.1°

3 figure bearing is thus 180 ° - 78.1 ° = 101.9 °

109.1 ° = N 11.9 ° W

Why 109.1 ° = N 11.9 ° W.

2. Sep 7, 2009

It isn't: the result is $$101.9^\circ$$, not $$109.1^\circ$$. With N at $$90^\circ$$, the result is $$11.9^\circ$$ west of that, hence the $$N 11.9^\circ W$$.