有圆规画一个直径为8厘米的圆,圆规两脚间的距离应取 厘米.
÷25== = (小数)= %= 成.
12: == :4=0.25= 折.
=2: =4÷ = %=0.2.
12÷ = :12=0.75= = %
0.75=6÷ = :12== %