As shown in the figure, in rectangle ABCD, ab = 16, BC = 8, fold the rectangle along AC, point d falls at point E, and CE and ab intersect at F, then AF=______ .

As shown in the figure, in rectangle ABCD, ab = 16, BC = 8, fold the rectangle along AC, point d falls at point E, and CE and ab intersect at F, then AF=______ .

From the properties of folding, we can get △ AEC ≌ △ CBA ﹥ ACF = ∠ caf ﹥ AF = cf. in RT △ CFB, from Pythagorean theorem, we can get CB2 + BF2 = CF2, that is 82 + (16-af) 2 = af2, and AF = 10