延长AB、DC相交于点M,
延长CD、FE相交于点N,
延长EF、BA相交于点P,
则有：△ACM、△DEN、△FAP、△MNP 都是等边三角形.
DE+EF+FA = NE+EF+FP = NP = MN = MC+CD+DN = BC+CD+DE = 9+9+7 = 25 ；
该六边形的周长为 AB+BC+CD+DE+EF+FA = 1+9+9+25 = 44 .