Before revision: T: 092° V: +3° M: 089° D: -4° C: 093° Thus, when following a compass course of 093°, the true course is 086 °.
After revision: T: 092° V: +3° M: 089° D: -4° C: 093° Thus, when following a compass course of 093°, the true course is 092 °.