题目

如图点D,C在线段BF上,且BD=CF,∠B=∠F, 。求证:AC=ED. 答案:证明:∵BD=CF∴BD+CD=CF+CD,即BC=FD;∵DE∥AC,∴∠EDC=∠ACB;在△ACB和△EDF中∠B=∠FBC=FD∠ACB=∠EDC∴△ACB≌△EDF(ASA)∴AC=ED.
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