What is the requirement for the sum of deflection angles in a closed traverse?

In a closed traverse, the requirement for the sum of deflection angles is that it must equal 360 degrees. This is because a closed traverse forms a loop where the start and end points are the same, effectively creating a complete circuit. Each deflection angle corresponds to a change in direction as the surveyor moves from one point to the next.

When adding all the angles of change (deflection angles) around the loop, they must total 360 degrees to account for the complete rotation around the endpoint back to the starting point. If the angles did not sum to 360 degrees, it would indicate either an error in measurements or an incomplete loop. Thus, the condition ensures geometric closure in survey lines, making it a foundational concept in surveying practices. The other options do not apply to a closed traverse, as they refer to angles that do not accurately reflect the necessary angular sum required for a full circuit.