The problem is: "Prove analytically that that the sum of the squares of the medians of a triangle are equal to three-fourths the sum of the squares of the sides."

What I tried: I set up three points, (a,b), (c,d), and (e,f) to represent all three sides of the triangle, then I found the midpoints of each, getting, ((a-c)/2,(b-d),2), ((c-d)/2,(d-e)/2) and ((a-e)/2,(b-f)/2) then I tried finding all the distances using the distance formula, and that's when I realized I must be doing something wrong. 

I can't figure this out, does anybody know what to do?