Question

The magnetic bearing of a line AB is  48°24. Calculate the true bearing if the magnetic declination is E 5°38.
1. 42°44'
2. 20°56'
3. 54°02'
4. 53°98'
5. 59°28'

Answer 1

Correct Answer - Option 3 : 54°02'

Concept:

Magnetic declination: At any place horizontal angle between true meridian and magnetic meridian is called magnetic declination

For Eastern Declination:

α = β + θe or T.B = M.B + θe

Here, α = True bearing (T.B)

β = Magnetic bearing (M.B), and

θE = Eastern declination

For Western Declination:

α = β – θw or T.B = M.B – θw

Here, θw = western declination.

Calculation:

Magnetic bearing of a line AB = 48° 24’

∴ True bearing = 48˚24’ + 5°38’ = 54° 02’