一个圆柱的底面直径是10cm,高12cm,它的侧面展开图的周长是 cm.
3:8=18÷ ═ %= .小数.
÷8===15÷ = ÷32= (填小数)
0.3==12÷ = :30= %
÷40=20: =0.8= : .
3÷ == :12=六成= %