已知：如图AB∥CD,AE⊥DC,AE=12,BD=15,AC=20,试求梯形ABCD的面积.

如图,已知AE=DE,AE⊥DE,AB⊥BC,DC⊥BC.求证:AB+CD=BC 已知：如图AB∥CD,AE⊥DC,AE=12,BD=15,AC=20,试求梯形ABCD的面积. 已知；如图,AB∥CD,AE⊥DC垂足为E,AE=12,BD=15,AC=20.求梯形ABCD的面积 如图:已知AE=DE,AE垂直DE,AB垂直BC,DC垂直BC.求证AB+CD=BC 如图,AE⊥AB,BC⊥AB,CD⊥ED,ED=DC.求证：AE+BC=AB. 如图,已知AB∥CD,AD⊥DC,AB=BC,且AE垂直BC.①求证:AD=AE;②若AD=8,DC=4,求AB的长. 已知:如图,AD=CD CE=BF DF=AE 求证AB‖DC 已知:如图,在梯形ABCD中,AB//CD,AE⊥DC,BD⊥AC,AE=12,BD=20,求梯形ABCD的面积? 已知如图,AB//CD,AE⊥DC,AE=12,BD=15,AC=20,则梯形ABCD的面积是( ) 如图,已知：AB=DC,DE⊥AC,BF⊥AC,E,F是垂足,AE=CF.求证：CD∥AB. 如图,在直角梯形ABCD中,AB∥CD,AD⊥DC,AB=BC,且AE垂直BC 如图 已知ab垂直bc CD垂直BC AB=4 BC=7 CD=3 AE=DE 求证AE垂直DC 如图,已知BE=DF,AE=CF,AE∥CF,说明AB∥CD 如图,已知AE等于DE,AE垂直DE,AB垂直BC,DC垂直BC,求证：AB+CD等于BC. 如图,已知AE⊥AD,AF⊥AB,AB//CD,AE=CD,AE=AD,AF=CD,求证AC=EF 如图,已知AE/EB=DF/FC=/,求AB/EB,DC/FC,AB/AE,DC/DF的值 如图,已知AB平行DC,AB=DC,AE=CF,求证：BF=DE 如图,已知AE⊥AD,AF⊥AB,AB∥CD,AF=CD,AE=AD,求证：AC垂直EF.