一个正方体的棱长扩大2倍,它的表面积扩大4倍. .
= ÷32=( 0.125 )填小数=6:( )=12.5%.
== :32=15÷ = (填小数)
=18: =0.6== %= 折.
÷6=6: =1.5= %
15÷ ===1=1.25.