Forget it, let me tell you! (* _ _ *) Hee hee

5.8 cm

8.FG is perpendicular to DE and connects EG and DG. Because DG and EG are the midpoint of BC, EG=DG.

So ∠GED=∠EDG, because F is the midpoint of ED and GF is perpendicular to ED, FG divides DE vertically.

I am very unhappy when I play. Sometimes I speak Chinese and sometimes I speak English. Give me extra points! ! ! ! ! ! !