# If the fore bearing of a line AB is 40° 15', then what will be the fore bearing of line BA?

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If the fore bearing of a line AB is 40° 15', then what will be the fore bearing of line BA?
1. 130° 15'
2. 40° 15'
3. 139° 45'
4. 220° 15'

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Correct Answer - Option 4 : 220° 15'

Explanation:

FB of line BA is BB of line AB.

The relation b/w FB and BB of a line is given as;

BB = FB ± 180°

If FB > 180° then use minus sign

If FB ≤ 180° then use plus sign

Given that FB of AB = 40° 15’ i.e. less than 180°. So, we will use plus sign.

BB of AB = FB of BA = FB of AB + 180° = 40° 15’ + 180°

∴ FB of BA = 220° 15’