From true direction to magnetic direction: which statement correctly describes the conversion steps?

From true direction to magnetic direction: which statement correctly describes the conversion steps?

• A. From true to magnetic: Add easterly variation to true direction and subtract westerly variation from true direction
• B. From true to magnetic: Subtract westerly variation from true direction and add easterly variation to true direction
• C. From true to magnetic: Subtract easterly variation from true direction and add westerly variation to true direction
• D. From true to magnetic: Add westerly variation to true direction and subtract easterly variation from true direction

Answer: (D)

Converting from true direction to magnetic direction uses the variation between true north and magnetic north. To aim toward magnetic north, you adjust the true direction by the variation: add the westerly variation and subtract the easterly variation. This matches the common rule “west is best, east is least” when moving from true to magnetic, and it works whether the variation is west (you add it) or east (you subtract it). So the statement that describes adding westerly variation to the true direction and subtracting easterly variation fits the standard method. For example, with a true direction of 090° and a west variation of 5°, the magnetic direction is 095°. With a true direction of 090° and an east variation of 5°, the magnetic direction is 085°.

Converting from true direction to magnetic direction uses the variation between true north and magnetic north. To aim toward magnetic north, you adjust the true direction by the variation: add the westerly variation and subtract the easterly variation. This matches the common rule “west is best, east is least” when moving from true to magnetic, and it works whether the variation is west (you add it) or east (you subtract it).

So the statement that describes adding westerly variation to the true direction and subtracting easterly variation fits the standard method. For example, with a true direction of 090° and a west variation of 5°, the magnetic direction is 095°. With a true direction of 090° and an east variation of 5°, the magnetic direction is 085°.