It is known that a, F, C and D are on the same straight line, AC = DF, ab ‖ De, EF ‖ BC. Try to explain: (1) ABC ≌ def; (2) CBF = FEC

It is known that a, F, C and D are on the same straight line, AC = DF, ab ‖ De, EF ‖ BC. Try to explain: (1) ABC ≌ def; (2) CBF = FEC

It is proved that: (1) in △ ABC and △ def, in △ ABC and △ def, ∠ a = DAC = DF ∠ EFD = BCA, ‖ ABC ≌ def (ASA); (2) in △ ABC ≌ def, ‖ EF = BC ≌ EF ‖ BC, EFBC, EFBC, EFBC, EFBC, EFBC, EFBC are parallelograms, CBF = FEC