So you're going to have o draw this out... I mean if you draw it out accurately, you should be able to guess it...
But let's do it the mathematical way!
So the change in height from the base to the top height is from y-coordinate(E) to y-coordinate(F) so you get the change in height to be 4. Thus the center height would be 4/2 + y-coordinate(E) or 2+1=3
Now the change in the base would be x-coordinate(E) - x-coordinate(D) which would be 6 so being half way through the base would get you 3 x units away from the x-coordinate(D) which would be 4
Thus the center should be at (4,3)