已知:如图,AB=AC,AE=AF,且∠EAB=∠FAC,EF=BC.求证:四边形EBCF是矩形.

如图,三角形ABC中,AB=AC,且AE=AF,求证EF垂直BC 已知:如图,AB=AC,AE=AF,且∠EAB=∠FAC,EF=BC.求证:四边形EBCF是矩形. 如图,AD是三角形ABC的中线,AE垂直AC,AF垂直AB,且AE=AC,AF=AB,求证：AD=1/2EF 已知：如图,AB=AC,AE=AF,AE⊥EC,AF⊥BF,则∠1=∠2吗?为什么? 已知:如图,AB=AC,AE=AF,AE⊥EC,AF⊥BF,则∠1=∠2吗?为什么? 如图9,AD//BC,AE⊥AD且AE=AD,AF⊥AB且AF=AB.则AC与EF是否相等?为什么? 已知,如图,在△ABC中,AB=AC,AE是C边上的中线,AF是∠CAD的平分线,求证:AE⊥AF 已知,如图,在△ABC中,AB=AC,AE是C边上的中线,AF是∠CAD的平分线,求证:AE⊥AF 如图,已知AE⊥AD,AF⊥AB,AB//CD,AE=CD,AE=AD,AF=CD,求证AC=EF 如图8,已知:AE⊥AB,AF⊥AC,AE=AB,AF=AC.试证明:(1)CE=BF;(2)CE⊥BF 如图,AD∥BC,AD=BC,AE⊥AD,AF⊥AB,且AE=AD,AF=AB,求证：AC=EF. 如图 ,.已知AF=AB,AE=AC,∠BAF=∠CAE说明∠1=∠2 如图,已知AB=AD,AC=AE,∠BAE=∠DAC,求证,AH=AF 如图,已知AE=AB,AF=AC,EC=BF,求证:∠BAE=∠CAF 如图,已知AD//BC,AD=BC,AE⊥AD,AF⊥AB,AE=AD,AB=AF.求证：AC=EF. 如图,已知AE⊥AD,AF⊥AB,AF=AB,AE=AD=BC,AD‖BC,求证AC⊥EF 如图,已知AE⊥AD,AF⊥AB,AB∥CD,AF=CD,AE=AD,求证：AC垂直EF. 已知：如图,AB=AC,点D,E分别在AC,AB上,AG⊥BD,AF⊥CE,垂足分别为G,F,且AG=AF.求证：AD=AE