Traverse bearing computation: apply interior angle at station B Given bearing of AB = 152° 30′. The interior angle ABC measured clockwise at B is 124° 28′ (from BA to BC). Compute the whole-circle bearing (WCB) of BC.

Introduction / Context:
Traverse computations often require converting a known line bearing and an interior angle at the next station into the bearing of the following line. Careful handling of fore and back bearings and the clockwise/anticlockwise sense of the measured interior angle is critical for correct results.

Given Data / Assumptions:

• Bearing of AB (WCB): 152° 30′.
• Angle ABC at station B is measured clockwise from BA to BC and equals 124° 28′.
• Whole-circle bearings are measured clockwise from north (0° to 360°).

Concept / Approach:

At station B, the reference direction along BA has the back bearing of AB. Compute BA’s bearing at B by adding 180° to AB (modulo 360°). Then, turn the given interior angle clockwise from BA to reach BC. Normalize to 0°–360° as needed.

Step-by-Step Solution:

Verification / Alternative check:

A quick sketch with north lines at A and B confirms the quadrant and magnitude. The result lies in the first quadrant, consistent with adding a 124° 28′ clockwise turn from a bearing near north-west (332° 30′) past north into the east quadrants.

Why Other Options Are Wrong:

27° 52′, 148° 08′, and 186° 58′ correspond to incorrect addition/subtraction or wrong use of fore vs back bearing; 316° 58′ is a common error from subtracting instead of adding the interior angle.

Common Pitfalls:

Forgetting to convert AB to BA at station B; mixing clockwise/anticlockwise sense; failing to wrap angles to 0°–360° correctly.

Final Answer:

96° 58′