等高的两圆柱的底面半径是3:2,它们的体积比是9:4. .
( )+= ×=÷ = ﹣= :4=0.5.
÷ ==30: =1.2= %.
÷5=1.2==30: .
+=0.8= : = %
3: == ÷25= %= (填小数)