As shown in the figure, fold the four corners of rectangle ABCD inward to form a seamless quadrilateral efgh, eh = 12cm, EF = 16cm, then the length of side ad is () A. 12 cm B. 16 cm C. 20 cm D. 28 cm
Let P and Q be the two points on the oblique line respectively, P and p be the point B folded in half, Eph be the right angle, △ AEH ≌ △ Peh, hea = ∠ Peh, similarly, PEF = ∠ bef, Peh + PEF = 90 degree, efgh be the rectangle, DHG ≌ △ BFE, HEF be the right triangle, BF = DH = PF, ≌ ah = HP, ≌ ad = HF, ∥ eh = 12cm, EF = 16cm, ∥ FH = Eh2 + ef2 = 122 + 162 = 20cm, FH = ad = 20cm C