由旋转可得：∠ABC=∠CBC',AC=AC'∵AB=AC,AB=A'B∴∠BAA'=∠BA'A,A'B=A'C'∴∠A'BC'=∠A'C'B∵AB=AC,∴∠ABC=∠ACB∴∠ABC=∠ACB=∠A'BC'=∠A'C'B设∠ABC=X,则X+2X+2X=180∴X=36°，即∠ABC=36°
