已知：如图,AB=AC,AE=AF,AE⊥EC,AF⊥BF,则∠1=∠2吗?为什么?

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 已知：如图,EF‖BC,AE²=AD·AB.求证：DF‖EC.【EF‖BC,平行线分直线,成比例AE/AB=AF/AC,AE²=AD·AB,AD/AE=AE/AB=AF/ACDF‖EC】这是解法、可是为什么AD/AE=AE/AB=AF/AC,DF就平行EC、要理由 已知：如图,EF‖BC,AE²=AD·AB.求证：DF‖EC.【EF‖BC,平行线分直线,成比例AE/AB=AF/AC,AE²=AD·AB,AD/AE=AE/AB=AF/ACDF‖EC】这是解法、可是为什么AD/AE=AE/AB=AF/AC,DF就平行EC、要理由 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,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? 已知:如图,在△ABC中AB=AC,AE是BC边上的中线AF是角CAD的平分线求证AE垂直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 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 全等三角形证明题(初二上册)如图,已知AD为△ABC中线,AB⊥AE,AB=AE;AC⊥AF,AC=AF,求证：EF=2AD(注:未说AB=AC) 如图所示,已知AE垂直AB,AF垂直AC,AE=AB,AF=AC,求证.EC垂直BF 如图所示,已知ae⊥ab,af⊥ac,ae=ab,af=ac.求证ec⊥bf 如图,已知AB=AD,AC=AE,∠BAE=∠DAC,求证,AH=AF 如图 ,.已知AF=AB,AE=AC,∠BAF=∠CAE说明∠1=∠2 如图,已知AE=AB,AF=AC,EC=BF,求证:∠BAE=∠CAF