dfasfafafa1 ,
设三个切点分别是F,G,H,DE的切点是P.则：
BF＝BH,CG＝CH,DF＝DP,EG＝EP
BC＝BF＋CG
DE＝DF＋EG
△ADE周长＝AD＋AE＋DE＝AF＋AG＝4
△ABC周长＝AB＋AC＋BC＝AF＋AG＋BF＋CG＋BC＝4＋2BC＝8．
△ABC周长是8㎝.