[Nisgeis]

Relative means relative to your own boat, with 000 being your own bow, so a target that is at a relative bearing of 090 is on your starboard beam when you are pointing North. If your boat were turned without moving forward or backward through 180 degrees to point due South, then the target would be be at a relative bearing of 270. The True bearing doesn't change, as that's taken relative to North, with North being 000, so with your boat pointing North, the true bearing would be 090 and with yout boat pointing South, the target would still be at a true bearing of 090.