设DC=x.⊿ADE∽⊿ACB ∴﹙3-x﹚/3=x/2 x=6/5
AD=3-6/5=9/5
△ADE,△EFB,△ACB周长之比=9/5∶6/5∶3=3∶2∶5
△ADE,△EFB,△ACB面积之比=9∶4∶25