Bearings terminology for a line AB: For two stations A and B, which statements about the fore bearing and back bearing of line AB are correct?

Introduction / Context:
Consistent use of fore and back bearings is essential in traverse computations and checks. Knowing their relationship helps detect local attraction and arithmetic errors during fieldwork and plotting.

Given Data / Assumptions:

• A reference meridian (true, magnetic, or grid) is fixed for both directions.
• Bearings are measured by the same system (whole-circle or quadrantal).
• Line AB is observed in both forward and reverse directions.

Concept / Approach:
The fore bearing (FB) is the direction of AB measured at A. The back bearing (BB) is the direction of the same line measured at B toward A. When using the same meridian and system, BB = FB ± 180°, adjusting to the 0°–360° or appropriate quadrantal range. This identity underpins the local-attraction test by comparing observed FB and computed BB.

Step-by-Step Solution:

Verification / Alternative check:
Traverse notes routinely compute a check value by FB − BB ≈ ±180°. Significant deviation flags local attraction or recording errors.

Why Other Options Are Wrong:

• Any single statement alone is incomplete; the inclusive option reflects complete practice.

Common Pitfalls:
Mixing whole-circle with quadrantal bearings; forgetting to normalize to 0°–360°; using different meridians for FB and BB.

Final Answer:
All of the above