Find back bearings:

Following are the observed fore bearings of the lines. Find their back bearings:

AB  42^o 34′,     BC 163^o 46′

CD  204^o 29′,  DE 337^o 52′

(c)                                                        (d)

Figure : BB from FB

(a)        FB of AB  = 42^o 34′

Back bearing of line AB

= Fore bearing of AB + 180^o

= 42^o 34′ + 180^o

= 222^o 34′

(b)       FB of BC  = 163^o 46′

Back bearing of line BC

= Fore bearing of BC + 180o

= 163^o 46′ + 180^o

= 343^o 46′

(c)        FB of CD  = 204^o 29′

Back bearing of line CD

= Fore bearing of BC - 180^o

= 204^o 29′ - 180^o

= 24^o 29′

(d)       FB of DE  = 337^o 52′

Back bearing of line DE

= Fore bearing of DE - 180^o

= 337^o 52′ - 180^o

= 157^o 52′