Two lines AB and BC have bearings of 60^ exto and 120^ exto respectively. i) Correct the discrepancy between the lines & ii) Write down the correct bearing of the line.

i) Correct the discrepancy between the lines & ii) Write down the correct bearing of the line.

Step 1: Identify stations free from local attraction.
The difference between the forward bearing (FB) and back bearing (BB) for a line should be exactly $180^\circ$ if there is no local attraction.

• For line AB-BA: $\text{BB(BA)} - \text{FB(AB)} = 240^\circ - 60^\circ = 180^\circ$. This indicates that stations A and B are free from local attraction.
• For line BC-CB: $\text{BB(CB)} - FB(BC) =