Answer:
18
Explanation:
Since we know that the length of segment CG is 6 units greater than the length of segment DG, we just multiply it by 2. We multiply it by 2 because a centroid will always have a line segment that in in a 2:1 ratio. Since CG is twice the size of DG, we just mutiply it by 2, then add the original number.
6+6=12
12+6=18