The area is 40*0.5*55= 1 100.

2、B

3、2 & ltX & lt 10

4. The solution ∵ABCD is a parallelogram.

∴∠DAC=∠ACB,AO=CO,AD=BC

180 -∠DAC= 180 -∠ACB

That is ∠EAC=∠ECA.

∠∠AOF and ∠COE are diagonal.

∴∠AOF=∠COE

∴△AOF≌△COE

Available, AF=CE

Once again: AD = BC

∴AF+AD=BC+CE

That is, BE=DF.

5. Solution: Connect MD and NB

∵ABCD is a parallelogram.

∴AO=CO,BO=DO

∵M and n are the midpoint of AO and CO, respectively.

∴OM=ON

The available BMDN is a parallelogram.

∴BM=DN

BM‖DN

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