In class, Teacher Zhou showed the following questions. Xiao Ming and Xiao Cong perform on the blackboard respectively. Please also answer this question: on the rectangle AB.

Solution: (1)∵ From folding, it can be known that △ABE is an isosceles right triangle.

∴AE = ab = 20cm；

(2) ∵ According to the folding, AG=AB, ∠GAE=∠BAE, ∵ Point P is the midpoint of AB,?

∴ AP= AB，∴ AP= AG，？

In Rt△APG, ∠ gap = 60, ∴ ∠ EAB = 30,

In Rt△EAB, AE= AB= cm.

(3) EH⊥AD is at point H, even BF. From folding, we know that DE=BE,

AF = FG，DF=AB，GD=AB，

∴△abf?△GDF, and: △△GDF =∠CDE, GD=CD,

? ∴ Rt△GDF≌Rt△CDE

∴ DF=DE=BE，

At Rt△DCE, DC 2 +CE 2 =DE 2.

CB = 25，CD=20，20 ^ 2+ce2 =(25-CE)2，

∴ CE=4.5，BE=25-4.5=20.5，HF=20.5-4.5= 16，

At Rt△EHF,

∫EH 2+HF 2 = Fe2，20 2 + 16 2 =FE 2，？

∴ EF= = cm