Two beacons form a range in the direction of 221.5°T. The range is seen in line from your vessel bearing 223° per gyro compass. The variation in the area is 4°E. What is the error of your gyro compass?

Correct Answer: Option A — 1.5°W

Compass error is the algebraic sum of variation and deviation. Comparing a known true range of 221.5°T against the gyro bearing of 223° pgc establishes a gyro error of 1.5° West (East is least, West is best).