Question

The fore bearing of a line AB was observed to be 245${}^o$30', and it is known that station A is free of local attraction. The declination at the place was found to be 3${}^o$15'W. Find the true bearing of line BA.

• A. 62${}^o$15'
• B. 62${}^o$30'
• C. None of these
• D. 65${}^o$30'

Answer 1

The correct option is A 62${}^o$15'

First we correct the bearing for local attraction.
Correct back bearing of line AB should be equal to 245${}^o$30' - 180${}^o$ = 65${}^o$30'

$\therefore$ True back bearing of AB = Magnetic bearing - West declination

= 65${}^o$30' - 3${}^o$15'
= 62${}^o$15'

$\therefore$ True back bearing of line AB = True bearing of line AB = 62${}^o$15'