Notam AD ∩ BF = G
BF - bisectoare => ∡ABG ≡ ∡GBD
BG ≡ BG } => (C.U.) => ΔABG ≡ ΔGBD =>
=> BA ≡ BD
ΔABG ≡ ΔGBD => AG ≡ GD
BG ≡ BG } => (C.U.) => ΔAGF ≡ Δ GDF =>
=> ∡CAD ≡ ∡EDA
DC ≡ AE } => ΔCAD ≡ ΔEDA => AC ≡ DE
AD ≡ AD
∡EFA ≡ ∡CFD
DC ≡ AE } => ΔEFA ≡ ΔCFD => FC ≡ EF
FD ≡ AF