It is known that in △ ABC, ad is the bisector of ∠ BAC outer angle ∠ EAC, and D is the intersection of bisector and BC extension Don't copy the answer

It is known that in △ ABC, ad is the bisector of ∠ BAC outer angle ∠ EAC, and D is the intersection of bisector and BC extension Don't copy the answer

First, do ∠ EDA = ∠ ADC, ∵ ad bisection ∠ EAC, ∵ DAE = ∠ DAC, and ad is the common edge of △ DAE and △ DAC, ≌ △ DAB, ≌ △ AED = ∠ ACD, de = CD, and then take a point F on the straight line BAE, so that DF = De, then △ DFE is isosceles triangle, ≌ def = ∠ DFE, ≌ DEA + ∠ DFA = 180 = ∠ ACD + ACB, ≌