已知圆柱的底面半径是2厘米,侧面积是62.8平方厘米,则它的高是 厘米.
:10=18: =50%=6: = ÷60.
35: =20÷16== %= (填小数)
:3=10: ==1.5: .
30:42==45÷ ≈ %.
÷ == %= : = = 成.