解析,由于,DE∥FG∥FB,AD:DF:FB=1:1:1
那么,AD:AF:AB=1:2:3
所以,S△ADE∽S△AFG∽S△ABC,并且S△ADE:S△AFG:S△ABC=1:2²:3²=1:4:9
设S△ADE=a,那么,S△AFG=4a,S△ABC=9a
S(四边形DEFG)=S△AFG-S△ADE=3a
S(四边形FGCB)=S△ABC-S△AFG=5a
那么,S△ADE:S(四边形DEFG):S(四边形FGCB)=a:3a:5a=1:3:5