【正文】
E D C B A ∵ AD ∥ BE ∥ CF, ∴ 平行線(xiàn)分線(xiàn)段成比例定理 … … O A B C D E Q M N P 已知:如圖, AB∥ GH∥ EF∥ DC, AB=30, CD=6, DE : EG: GA=1: 2: 3, 則 GH =_________, EF =________. F E D C B A G H 已知:如圖, AB∥ GH∥ EF∥ DC, AB=30, CD=6, DE : EG: GA=1: 2: 3, 則 GH =_________, EF =________. F E D C B A G H 30 6 已知:如圖, AB∥ GH∥ EF∥ DC, AB=30, CD=6, DE : EG: GA=1: 2: 3, 則 GH =_________, EF =________. F E D C B A G H 30 6 GH是梯形 ABCD的中位線(xiàn) 18 已知:如圖, AB∥ GH∥ EF∥ DC, AB=30, CD=6, DE : EG: GA=1: 2: 3, 則 GH =_________, EF =________. F E D C B A G H 18 M 18 已知:如圖, AB∥ GH∥ EF∥ DC, AB=30, CD=6, DE : EG: GA=1: 2: 3, 則 GH =_________, EF =________. F E D C B A G H