Section 4: Soil and Water Conservation Engineering
Surveying and Levelling
Subtopic: Measurement of angles and bearings
Question Statement:
The magnetic bearing of a field boundary line was surveyed as $\text{N } 45^\circ 30' \text{ E}$. If the magnetic declination at the location is $2^\circ 30' \text{ W}$, the true bearing of the line is:
Options:
(A) $\text{N } 43^\circ 00' \text{ E}$
(B) $\text{N } 48^\circ 00' \text{ E}$
(C) $\text{S } 43^\circ 00' \text{ W}$
(D) $\text{N } 45^\circ 30' \text{ W}$
Answer Key:
A
Step-by-Step Solution & Explanation
For a quadrant bearing in the NE quadrant:
$\text{True Bearing} = \text{Magnetic Bearing} - \text{West Declination}$
$\text{True Bearing} = 45^\circ 30' - 2^\circ 30' = \text{N } 43^\circ 00' \text{ E}$
Thus, Option A is correct.