∵D,F分别是BC,AC在中点∴DF||AB DF=AB/2∵E是AB中点∴AE=AB/2∴DF=AE∵EG||AD∴四边形AEGD中平行四边形∴AE=GD∴FG=DF+DG=2DF=AB
手写作出来的,满意请采纳