∠BAC=180-(∠ABC+∠C)=180-4∠C∠1=∠BAC/2=90-2∠C∠ABE=90-∠1=2∠C延长BE交AC于F因为,∠1 =∠2,BE⊥AE所以,△ABF是等腰三角形AB=AF,BF=2BE∠FBC=∠ABC-∠ABE=3∠C-2∠C=∠CBF=CFAC-AB=AC-AF=CF=BF=2BE
TAN(ACD)=AD/CD=1ACD=ARCTAN(1)=45也就是,只要其中角ACB等于45度,就可以使ADCE为正方形了。