∵AD⊥BC,A1D1 B1⊥C1,∴∠ADB=∠A1D1B1,又∵∠B=∠B1 ∴Rt△ADB∽△A1D1B1 ∴AB ：A1B1 = AD ：A1D1 而已知AB/A1B1= CD/C1D1 ∴AD ：A1D1 = CD/C1D1 ,且∠ADC=∠A1D1C1=90° ∴△ADC=△A1D1C1 ∴∠C=∠C1 而又∵∠B...