What term describes an azimuth obtained by adding or subtracting 180 degrees from the original azimuth?

The term that describes an azimuth obtained by adding or subtracting 180 degrees from the original azimuth is "Back azimuth." A back azimuth is necessary for navigators and those using compass skills, as it helps in determining the opposite direction from a given azimuth. To obtain a back azimuth, you simply add 180 degrees to your original azimuth if the result is less than 360; if it is 360 or greater, you subtract 360 from the sum. If subtracting, you would typically do so from an azimuth that is initially greater than 180 degrees. This concept is crucial in navigation, land surveying, and various military applications, ensuring that individuals can effectively orient themselves in relation to their starting point or destination.