解:(1)过点D作DE⊥BC;
∵AH⊥BC,DE⊥BC,且AD∥BC;
∴AH=DE,且AD=EH;
又∵在Rt△AHB中,AB=8,∠B=60°;
∴DE=AH=AB•sin60°=4√3cm
∴在Rt△DEC中,CD=DE/sin45°=4√6cm;
(2)∵BH=AB•cos60°=4cm,CE=DE=4√3cm,且EH=AD=5cm;
∴BC=BH+EH+CE=(9+4√3)cm
∴梯形ABCD的面积为S=½•(AD+BC)•AH=½×(9+4√3)×4√3
=(24+18√3)cm².
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