Using the algebraic sums of the latitude and departures, the hypotenuse may be computed.

For a tangent of theta 1, divide the opposite side by the adjacent side, 0.25 divided by 40 equals 0.0063.

Invert that tangent, that is, find the arc tangent and we determine that the angle theta rounded is 21 minutes. Now subtract 21 minutes from West 90 degrees and our final true bearing for the east/west line is North 89 degrees, 39 minutes East.