一个长5cm、宽3cm的长方形按3:1放大,得到的长方形的长是 ,宽是 ,面积是 .
4÷ == :15== %=( 小数)
12: ==0.6=48÷ .
:30=30÷ === (小数)= 折.
75%= (小数)= (成数)= (折数)= : .
:40= =36÷ =0.45= .