三角形ABC周长=6+9+12=27(cm),a1/a=p1/p,(p1,p是二三角形周长)
27/81=9/a1,a1=27,27/81=b/b1=12/b1,b1=36,27/81=c/c1=6/c1,c1=18,
A1B1=18(cm),B1C1=(27(cm),A1C1=36(cm).
三角形ABC周长=6+9+12=27(cm),a1/a=p1/p,(p1,p是二三角形周长)
27/81=9/a1,a1=27,27/81=b/b1=12/b1,b1=36,27/81=c/c1=6/c1,c1=18,
A1B1=18(cm),B1C1=(27(cm),A1C1=36(cm).