Answer:
0.500
Explanation:
We presume your "centroid ratio theorem" tells you that AG = 2·DG, so ...
(x+7) = 2(x -15)
x + 7 = 2x - 30 . . . . eliminate parentheses
37 = x . . . . . . . . . . .add 30-x
Then AG = 37+7 = 44
and DG = 37-15 = 22.
Of course, AD = AG +GD = 44 +22 = 66
