トラバース角度の計算

Consider a closed traverse with four vertices. The azimuths of the two sides and the bearings of the other two sides are given. The objective is to find the internal angle at each vertex of the traverse. 

Firstly, the angle at A is calculated by subtracting 50 degrees, the azimuth of AB, and 75 degrees, the bearing angle of DA, from 180 degrees, resulting in 55 degrees.

Next, the angle at B is calculated by subtracting 120 degrees, the azimuth of BC, from 180 degrees and adding 50 degrees, the azimuth of AB, resulting in 110 degrees.

At C, the angle is calculated by subtracting 20 degrees, the bearing angle of CD, from 120 degrees, the azimuth of BC, resulting in 100 degrees.

Lastly, the angle at D is calculated by adding 75 degrees, the bearing angle of DA, to 20 degrees, the bearing angle of CD, resulting in 95 degrees.

To check the accuracy, the sum of all the internal angles is calculated, which turns out to be 360 degrees, indicating the correctness of the internal angles.