Solution:
To solve this problem, we need to know a principle:
The higher the angle is, the longer the side opposite the angle.
Since the largest angle is angle C which is 81 degrees, the side opposite it is the longest which is AB.
The second-largest angle is angle A which is 60.4 degrees and its opposite side is side BC.
The smallest angle is angle B which is 38.6 degrees with an opposite side of side AC.
ANSWER: AB, BC, AC (Last Option)
