A1B1=AB=2 A1C=A1B1-BC=2-1.7=0.3
S(AA1C)=A1C*AC/2=0.3*1/2=0.15
因为三角形A1B1C1是三角形ABC绕B旋转得到的，所以AB=A1B1=2,有因为BC=1.7，所以A1C=0.3，∵角ACB为90° ∴△AA1C是直角三角形，S△AA1C=½*0.3*1=0.15
