Question

If the bearing of a line AB is N 60° 30′ and that of BC is 122° of a closed traverse ABCDE, then the measure of the interior angle B is .......

• A. 240° 30′
• B. 122° 00′
• C. 118° 30′
• D. 154° 00′

Hint:

To calculate interior angles in a closed traverse using bearings, always convert quadrant bearings to whole circle bearings first, then apply the angle difference and adjust to get the interior angle.

Answer 1

The Correct Option is C

Step 1: Understand the bearings
Bearing of AB = N 60° 30′ → This is a quadrant bearing (NE quadrant).
Convert it to whole circle bearing (WCB):
WCB of AB = 60° 30′ (since it's NE quadrant)
Bearing of BC = 122° (already in whole circle bearing format)
Step 2: Use formula to compute interior angle
Interior angle at B = WCB of BC - WCB of AB
= 122° 00′ − 60° 30′
= 61° 30′
But this is the exterior deflection angle. For interior angle in a traverse,
Interior angle = 180° − Exterior angle
= 180° − 61° 30′
= 118° 30′
Step 3: Final Answer
The correct interior angle at B is 118° 30′.