∫ In Rt△ABC, AC=6CM, BC=8CM, and AB? =AC？ +BC？ =6? +8? = 10? ∴ AB =10: △ ABC crease makes point B coincide with point A, and the crease is de ∴ BE = AE =1/2ab =1/2 times 10CM=5CM.

∴AD+CD=BC=8CM∵ and AC=6CM∴AD in Rt△ACD? =AC？ +CD？ =6? +(8-AD？ )=36+64- 16AD？ +AD？ = 100- 16AD？ +AD？ The solution is AD=6.25CM, ∴ BD = ad = 6.25cm.