“AB:A1B1,=AC:A1B1=4:5,”打错.应该是:
“AB:A1B1,=AC:A1C1=4:5,”.
⊿ABC∽⊿A1B1C1.BC∶B1C1=4∶5.
设BC=4t.则B1C1=5t.BC+B1C1=45=4t+5t=9t.t=5.B1C1=5×5=25.
“AB:A1B1,=AC:A1B1=4:5,”打错.应该是:
“AB:A1B1,=AC:A1C1=4:5,”.
⊿ABC∽⊿A1B1C1.BC∶B1C1=4∶5.
设BC=4t.则B1C1=5t.BC+B1C1=45=4t+5t=9t.t=5.B1C1=5×5=25.