+130071 ED = (2/3) (20) = 40/3
ΔABF ~ EDF
AB / BF = ED / DF
20 / BF = (40/3) / DF
20 / (40/3) = BF /DF
60/40 = BF /DF
3/2 = BF /DF
So...there are 5 equal parts to BD and BF is 3 of them...so...
BF = (3/5)BD
And because FG is parallel to DC in triangle BDC...then...
FG / BF = CD /BD
FG / (3/5)BD = 20 / ( BD)
FG = (3/5)BD * 20 / BD = (3/5) * 20 = 12
