A:Va>Vb时:c (CH3COOH) +c (CH3COO-)>c (K+)
B:Va=Vb时:c (CH3COOH) +c (H+)>c (OH-)
C:Va<Vb时:c (CH3COO-)>c (K+)> c (OH-)> c (H)
D:Va与Vb任意比时:c (K+)+ c (H+)=c (OH-)+ c (CH3COO-)
用长4厘米、宽3厘米的长方形,照下图的样子拼成正方形.拼成正方形的边长最小是____厘米?