Draw a figure
Label the midpoint of BC as E and the midpoint of AC as f.
The intersection of the medians is P.
Length of BP = 8 and length PF = 4 because the intersection of the medians is at a point 2/3 of the distance from the vertex to the divided side; similarly length of AP = 6 and length of EP = 3.
Use the law of cosines to find the measure of angle APB; angle BPE is the supplement to angle APB.
Use angle angle BPE to compute the length of sides BC and AC.
Now you have the three sides of the triangle; use Heron's formula to compute the area.