Question

We should know the angle of declination of a place to know the actual geographical direction,why??

Answer 1

To find the exact geographic directions (North and South) at a place by using a magnetic compass, we should know the angle of declination at that place. ... For example a declination of 2 o E means the compass will point 2 degrees east of true geographical North.

Answer 2

The angle made by the intersection of the line joining the magnetic north south and the line joining the geographical north south at a place is called angle of declination. There is single value of angle of declination at a fixed place. Therefor, the value of angle of declination give the position of that place. So, to know the angle of declination of a place we should know the actual geographical direction.

Hope it helps you