What is the impact of Mag Var -7 to a given heading of 205?

Answer: B — It decreases the heading by 7 degrees

To understand the impact of a magnetic variation (Mag Var) of -7 on a heading of 205 degrees, it is essential to comprehend the relationship between magnetic headings and true headings. Magnetic variation represents the difference between magnetic north and true north, with a negative variation indicating that true north is to the east of magnetic north. In this case, a Mag Var of -7 means that the magnetic compass reading is 7 degrees west of true north. Therefore, when adjusting the magnetic heading to convert it to true heading, you would need to decrease the magnetic heading by the value of the magnetic variation. Starting from a magnetic heading of 205 degrees, you subtract the 7 degrees for the Mag Var. This results in a new heading of 198 degrees true heading. This adjustment reflects the fact that to align with true north, the heading must be reduced when dealing with a negative Mag Var.