Question

The fore bearing of a line is 30 degree. Calculate the back bearing of a line (in degree).

• A. 330
• B. 210
• C. 120
• D. 60

Answer 1

The correct option is B 210

Difference between the fore bearing and back bearing is ${180}^0$
$BB=FB\pm {180}^0$
Data given F.B = ${30}^0$

Case (1) : $BB=FB+{180}^0=30+{180}^0+{210}^0$

Case (II) : $BB=FB-{180}^0=30-{180}^0=-{150}^0$

$BB=-{150}^0+{360}^0={210}^0$