论文部分内容阅读
566.△ABC中,已知∠A=120°,AD、BE是△ABC的角平分线,求证:AB+AE=AD+BD.证:如图1,延长BA到F,使AF=AE;在
566. △ ABC, known ∠ A = 120 °, AD, BE is the angle bisector of △ ABC, confirmation: AB + AE = AD + BD. Certificate: As shown in Figure 1, extend BA to F, so that AF = AE ;in