Answer:
9
Explanation:
You have to read your givens carefully and then get rid of the information you don't need.
The key fact is that CM = 3
The centroid divides the median into a one to two ratio. So
1/2 = CM/DM where D is apex of the triangle. It is where two of the sides meet, plus the median going to C.
1/2 = 3/DM Cross multiply
DM = 2 * 3
DM = 6
Therefore the length of the median going to C is DM + CM = 6 +3 =9