Is it important to minimize yardage?
If that's not a problem, what I would do is use a piece of fabric a little more than 2.6 yards long. (2.5 yards = 90". You will need about 93" for the longest borders, and 93/36 = 2.6 yards) . From that I would cut 4 pieces along the length, each piece 6.5" wide. This would make each border a single piece of fabric cut along the lengthwise grain, which is the most stable grain and therefore desirable for borders. Leftovers would consist of a strip of fabric about 12" wide and 2.5 yards long.
I would sew the 90" (longest) borders first. That would make the shorter 80" sides 92.5" long (80+6.25+6.25). With 2.6 yards of fabric, each border would be a single lengthwise piece.
Note: I edited this to correct a few of the numbers.