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有一张矩形纸片ABCD,其中AD=4cm,上面有一个以AD为直径的半园,正好与对...
有一张矩形纸片ABCD,其中AD=4cm,上面有一个以AD为直径的半园,正好与对边BC相切,如图(甲).将它沿DE折叠,是A点落在BC上,如图(乙).这时,半圆还露在外面的部分(阴影部分)的面积是( )
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A.(π-2
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)cm
2B.(
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π+
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)cm
2C.(
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π-
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)cm
2D.(
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π+
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)cm
2
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