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在△ABC中,BC=10,B1、C1分别是图①中AB、AC的中点,在图②中,B1...
在△ABC中,BC=10,B
1、C
1分别是图①中AB、AC的中点,在图②中,B
1,B
2,C
1,C
2分别是AB,AC的三等分点,在图③中B
1,B
2…B
9;C
1,C
2…C
9分别是AB、AC的10等分点,B
1C
1+B
2C
2+…+B
9C
9的值是( )
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A.30
B.45
C.55
D.60
考点分析:
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A.
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D.
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1B
1C
1C;延长C
1B
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2C
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D.
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D.
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