E is on CD, f is a point on the extension line of BC, CE = CF (1) proves that triangle BCE congruent triangle DCF (2) ∠ FD E is on CD, f is a point on BC extension line, CE = CF (1) Proof of triangle BCE congruent triangle DCF (2) How much is ∠ FDC = 30 ° and ∠ bef = 0

E is on CD, f is a point on the extension line of BC, CE = CF (1) proves that triangle BCE congruent triangle DCF (2) ∠ FD E is on CD, f is a point on BC extension line, CE = CF (1) Proof of triangle BCE congruent triangle DCF (2) How much is ∠ FDC = 30 ° and ∠ bef = 0

It is proved that in triangle BCE and triangle DCF: BC = DC, angle BCE = angle DCF, CF = CE. According to SAS theorem, triangle BCE is equal to triangle DCF
Second question: because triangle BCE and triangle DCF are congruent, so angle BEC = angle DFC, and because CF = CE, so angle CFE = angle CEF = 45 °, so angle EFD = 60 ° - 45 ° = 15 °