Which expression defines the Target Angle TA?

• A. TA = TB + TC - 180
• B. TA = TB - 180 - TC
• C. TA = TB + OC - 180
• D. TA = TB + 180 - TC

Answer: (D)

Relating TA to TB and TC comes down to handling line directions correctly. If TB is the bearing of the line from your ship to the target, and TC is the bearing of the line from the target back to a reference, you must reverse the TC line to bring it into the ship’s perspective and then align with TB. Reversing a line is a 180-degree change in direction, so you add 180 to TB and then subtract TC to place the orientation properly. In formula form, TA = TB + 180 − TC. This yields the correct target angle once you wrap around 360 degrees if needed. For instance, with TB = 120° and TC = 80°, TA = 120 + 180 − 80 = 220°, which matches the geometry of the setup. The other forms miss the necessary reversal or combine the angles in a way that doesn’t reflect how the lines are oriented from the ship’s position.