Deflection-angle traversing: In a closed traverse where deflection angles are observed, the difference between the sum of right-hand deflections and the sum of left-hand deflections should be equal to which value for correct closure?

Introduction / Context:
Deflection angles record the change of direction from one traverse leg to the next as right-hand or left-hand turns from the forward extension of each line. For a closed polygonal traverse, the cumulative turning must return to the original direction to achieve closure, imposing a key check relation.

Given Data / Assumptions:

• Traverse starts and ends at the same station (closed polygon).
• Angles are recorded as right-hand and left-hand deflections.
• No gross blunders are present.

Concept / Approach:
Walking completely around a closed traverse, the net change in direction must equal a full revolution. Therefore, the algebraic sum of deflections equals ±360°. Expressed as separate right and left totals, the difference between the sums of right-hand and left-hand deflections must be 360°. Any significant departure indicates observational or booking errors that should be investigated and corrected.

Step-by-Step Solution:

Verification / Alternative check:
Converting the same traverse to interior angles should yield the familiar 180° * (n − 2) total for an n-sided polygon; both checks are consistent and complementary.

Why Other Options Are Wrong:

• 0°, 90°, 180°: These do not represent the full turn around a closed figure in deflection-angle notation.

Common Pitfalls:
Mixing right/left signs; skipping one deflection; failing to maintain the forward extension reference consistently between legs.

Final Answer:
360°