由1/2=9/18,2/3=12/18,4/9=8/18,
∴1/2<4/9<2/3,
(1)(1/2)×(4/9)÷(2/3)=1/3,
即1/3:1/2=4/9:2/3.
(2)(1/2)×(2/3)÷(4/9)=3/4,
即1/2:4/9=3/4:2/3.
(3)(4/9)×(2/3)÷(1/2)=16/27,
即4/9:1/2=16/27:2/3.
可以填:(1/3)(3/4)(16/27).
由1/2=9/18,2/3=12/18,4/9=8/18,
∴1/2<4/9<2/3,
(1)(1/2)×(4/9)÷(2/3)=1/3,
即1/3:1/2=4/9:2/3.
(2)(1/2)×(2/3)÷(4/9)=3/4,
即1/2:4/9=3/4:2/3.
(3)(4/9)×(2/3)÷(1/2)=16/27,
即4/9:1/2=16/27:2/3.
可以填:(1/3)(3/4)(16/27).