∠DCE = ∠DEC Given
DC=DE The converse of the Isosceles Triangle Theorem
∠ACB=∠DGE, ∠GEF=∠DEC Vertical angles are congruent
∠ACB∠GEF Transitive Property of Equation
DF=DB Given
DF-DC=DB-DE (not sure what reason to put here)
BC=FE Substition
∠B=∠F Given
ΔABC=ΔGFE ASA Triangle Congruent Theorem