See what you need on make up work.
Make-up work changes both sides of the fraction: it adds points you can earn and points possible. Your target percentage applied to the new, larger total gives the points the course must show; subtract what you already hold and the remainder is what the make-up work has to deliver. Expressed as a percentage of the make-up assignment, that is the score to aim for. Because the denominator grows too, adding make-up work occasionally raises the bar rather than lowering it — the full-credit figure shows the ceiling either way.
Score needed on make-up work
Points required = target % x (points possible so far + make-up points) - points earned
Yes, if you score on it below your current average. It adds to the points-possible denominator whether or not you earn the points, so a weak make-up performance dilutes a strong record.
Then the target is out of reach through this route. The full-credit figure is your ceiling — use it to decide whether to petition for additional credit or to re-aim at a lower boundary.
Yes. The required percentage is the threshold; anything above it clears your target and anything below leaves a shortfall proportional to the gap.