(1)FC*FB=FE*FD,FC/FD=FE/FB,夹角相等同为∠F
△AEC相似于△ABD
∠ABC=∠CEF=∠AED
∠A共有
△ABC相似于△ADE
(2)AD/AC=AE/AB=DE/BC
AD+DE+AE=(AB-AD)+BC+(AC-AE)+DE
AB、BC、AC已知,联立上二式即得
(1)FC*FB=FE*FD,FC/FD=FE/FB,夹角相等同为∠F
△AEC相似于△ABD
∠ABC=∠CEF=∠AED
∠A共有
△ABC相似于△ADE
(2)AD/AC=AE/AB=DE/BC
AD+DE+AE=(AB-AD)+BC+(AC-AE)+DE
AB、BC、AC已知,联立上二式即得