9th grade
posted by Anonymous .
In triangle ABC, centroid D is on median line. AD=x+4 and DM=2x4. Find AM

The centroid divides a median in the ration of 2:1, the longer part towards the vertex.
so (x+4)/(2x4) = 2/1
solving....
x = 4
then AM = x+4 + 2x4
= 3x
= 12