1.AE=t DC=2t,∵∠C=30∴DF=t∴AE=DF2.当四边形AEFD为菱形时,AD=DF=t∵BC=5倍根号3,∠C=30°,∴AC=10,手差歼指AD=5∴AC=AD+DC=t+2t=3t=10 t=10/3<5∴当t=10/3时,四边形AEFD能够成毕改皮为菱形3.∵△DEF与△ABC相似∴DE∥BC∴t=AE=DF=1/2AB=2.5
1.AE=t DC=2t,∵∠C=30∴DF=t∴AE=DF
好题