Solution:-
In the table of natural sines, look for a value (≤ .6371) which is sufficiently close to .6371.
We find the value .6361 occurs in the horizontal line beginning with 39o and in the column headed by 30’ and in the mean difference, we see .6371 – .6361 = .0010 in the column of 4’.
So we get, θ = 39o 30’ + 4’ = 39o 34’.