If I am not mistaken, there is a well-known result that says that the intersection of the 3 medians has co-ords:
That point of intersection is known as the centroid of the triangle. If the triangle were a flat triangular plate of uniform density, then the centroid is the centre of mass (used to be called the centre of gravity) of the plate.
To do your question using your high school co-ord geometry, you will have to find the equations of the 3 medians, and find the points of intersection of the appropriate pairs of medians.