What is the back azimuth of 181 degrees?

To determine the back azimuth of a given azimuth, you need to subtract 180 degrees from the initial azimuth if it is greater than 180 degrees, or add 180 degrees if it is 180 degrees or less. When the azimuth is 181 degrees, subtracting 180 degrees gives you 1 degree.

This calculation is based on the idea that an azimuth reflects a direction on a compass, where 0/360 degrees corresponds to north, 90 degrees to east, 180 degrees to south, and 270 degrees to west. Therefore, a back azimuth represents the opposite direction of the original azimuth, which in this case leads us to 1 degree. This explains why 1 degree is the correct response when finding the back azimuth of 181 degrees.