10.68 each for the 2 same length sides. The total of the 5 sides is 45.56 less the 3 sides which total 24.2 leaves 21.36 remaining for the 2 equal length sides. So divide 21.36 by 2 = 10.68
(45.56 - 24.2)/2 = 10.68
I’m pretty sure it would be a and b
787-10=777
777/3=259
259 multiples of 3