As shown in the figure, in the square ABCD, e is the midpoint of AB side, G and F are the points on AD and BC side respectively. If Ag = 1, BF = 2, ∠ GEF = 90 °, then the length of GF is______ .

As shown in the figure, in the square ABCD, e is the midpoint of AB side, G and F are the points on AD and BC side respectively. If Ag = 1, BF = 2, ∠ GEF = 90 °, then the length of GF is______ .

∵ quadrilateral ABCD is a square, ∵ a = ∵ B = 90 °, ∵ age + ∵ AEG = 90 °, ∵ BFE + ∵ Feb = 90 °, ∵ GEF = 90 °, ∵ GEA + ∵ Feb = 90 °, ∵ age = ∵ Feb, ∵ AEG = ∵ EFB. ∵ AEG ∽ BFE, thus corresponding edge proportion is deduced: aebf = agbe, and ∵ AE = be