As shown in the figure, rotate square ABCD around point a clockwise to get square aefg, edge FG and BC intersect at point h. verification: Hg = Hb

As shown in the figure, rotate square ABCD around point a clockwise to get square aefg, edge FG and BC intersect at point h. verification: Hg = Hb

It is proved that the connection ah. ∵ quadrilateral ABCD and aefg are all square, ∵ B = ≌ g = 90 °. Ag = AB is known from the title meaning. In RT △ AGH and RT △ ABH, ah = AHAG = AB, ≌ RT △ AGH ≌ RT △ ABH (HL), ≌ Hg = Hb