From magnetic to true, which steps are applied?

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

Answer: (C)

Converting from magnetic to true bearings uses the variation to adjust the magnetic direction. The variation tells how far the magnetic north is from true north. If the variation is easterly, magnetic north is east of true north, so you add that amount to the magnetic bearing to get the true bearing. If the variation is westerly, magnetic north is west of true north, so you subtract that amount.

So, to go from magnetic to true, add the easterly variation to the magnetic direction and subtract the westerly variation from the magnetic direction. This is the standard way to translate magnetic readings into true headings. The other options either apply variation to the true direction or use the opposite sign, which would yield an incorrect true bearing.