Posted by Anonymous on .
In triangle ABC, centroid D is on the median line segment AM. AD=x+4 and DM=2x4. Find AM.

GEOMETRY 
Steve,
AM = AD+DM = x+4+2x4 = 3x
we also know that AD = 2DM, so
AM = 3(2x4)
so, 3x = 6x12
x = 4
AM = 12