(b) 1 : 2

By mid-point theorem, in ∆s ODA, OCD, OBC, OBA respectively
\(\frac{EF}{AD} = \frac{FG}{DC}=\frac{GH}{CB}=\frac{HE}{BA}=\frac{1}{2}\)
If \(\frac{a}{b}=\frac{c}{b}=\frac{e}{f}=.............,\)
then each ratio is equal to \(\frac{a+b+c+e+.......}{b+d+f+........}\)
⇒ \(\frac{(EF+FG+GH+HE)}{(AD+DC+CB+BA)}\) = \(\frac{1}{2}.\)