正方形的边长扩大3倍,周长就扩大3倍,面积扩大6倍. .
÷4=25%= : =8÷ = 折.
0.75= : = :25= 折= %= (成数)
10: ==0.625=5÷ = %
12: = ÷25== (小数)= %
:8=8÷ == %= 小数.