等底等高的圆柱和圆锥,已知圆锥的体积是30立方厘米,圆柱的体积是 立方厘米.
0.4== : = %.
:20==24÷ = %=二成= 折.
:8=== %
4÷ = =0.25= :40= %.
÷10==4:5= (填小数)= %.