题目内容
如图,在△ABC中,AB=AC=a,BC=b(a>b).在△ABC内依次作∠CBD=∠A,∠DCE=∠CBD,∠EDF=∠DCE.则EF等于( )
A. | B. | C. | D. |
C.
试题分析: ∵AB=AC,∴∠ABC=∠ACB,又∵∠CBD=∠A,∴△ABC∽△BDC,同理可得:△ABC∽△BDC∽△CDE∽△DFE,∴,,,,∵AB=AC,∴CD=CE,解得:CD=CE=,DE=,EF=.故选C.
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