The true reduced bearing is N 5° 0' W and the magnetic declination is 2° E. Find the true bearing in the whole circle bearing system.
- A357°
- B5°
- C353°
- D355°Correct
Solution
Concept
A bearing N θ W in the reduced bearing system is equal to 360° - θ in the whole circle bearing system.
Formula
WCB = 360° - θ (for N θ W)
Step-by-step solution
1. The given bearing is a true reduced bearing: N 5° W. 2. It lies in the NW quadrant, so WCB = 360° - 5° = 355°. 3. This is already the true bearing, so the declination is not needed. 4. Answer = 355°, option (D).
Explanation
N 5° W lies in the fourth quadrant, so its WCB is 360° - 5° = 355°. The bearing is already true, so we do not apply the declination. Declination is needed only to convert between magnetic and true bearings.
Why the other options are wrong
A (357°): adds the 2° E declination, which treats the given bearing as magnetic. B (5°): ignores the W direction. C (353°): this is the magnetic bearing (355° - 2°), not the true bearing.
Shortcut
N θ W gives WCB = 360° - θ.
Common mistake
Applying the declination even though the bearing is already true.
Correct answer: D) 355°