Hi McDonnel,
Your target course is 76.
Funny thing is how i shortened the calculation in your example:
Since angles between your 3 bearings (b1,b2,b3) are both the same (11), you can just pick the middle bearing, recalculate it to absolute bearing by adding your course (Co) and add 90 degrees, which is 436 (-360 = 76)
If your angles are the same, course is logically perpendicular.
Don't forget that if the target would be moving to the left, you would be subtracting.