在ABC与A1B1C1中,AB=AC,A1B1=A1C1,BD⊥AC,B1D1⊥A1C1,垂足分别为D、D1,
问题描述:
在ABC与A1B1C1中,AB=AC,A1B1=A1C1,BD⊥AC,B1D1⊥A1C1,垂足分别为D、D1,
且BD/B1D1=BC/B1C1,求△ABC∽△A1B1C1
答
BD/B1D1=BC/B1C1
角BDC=角B1D1C1=90
△BDC∽△B1D1C1
=>
角C=角C1
角BAC=180-2角C=180-2角C1=角B1A1C1
AB/A1B1=AC/A1C1
=>
△ABC∽△A1B1C1