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—43— —44—
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34ABCD9EFW40cm,AB∶BC=2∶3,�CDZAD9F.
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∵AD∥BC,∴∠BEA=∠DAE.
�∠BAE=∠DAE,∴∠BEA=∠BAE,∴AB=BE.
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BC=3+4=7(cm).
①¡BE=4cm¸,AB=BE=4cm,
ABCD9EFW2(AB+BC)=2(4+7)=22(cm);
②¡BE=3cm¸,AB=BE=3(cm);
ABCD9EFW2(AB+BC)=2(3+7)=20(cm).
∴ABCD9EFW22cmr20cm.
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