Solution: ∫ two right angles AC=6cm, BC=8cm,

According to Pythagorean Theorem, AB= 10,

Now the right angle AC is folded in half along the straight line AD, so that it falls on the hypotenuse AB and coincides with AE, then CD=DE, AE=AC=6,

∴BE= 10-6=4，

Let CD=x, then BD↑2=DE↑2+BE↑2,

That is, (8-x)2=x2+42,

X = 3。 That is, the length of the CD is 3 cm.

Pure handwriting, give points, we just learned, the teacher said.