单选题
In the figure above，O and P are the centers of two circles．If each circle has radius r，what is the area of the shaded region?
In the figure above，O and P are the centers of two circles．If each circle has radius r，what is the area of the shaded region?
【正确答案】
B
【答案解析】在上面的图形中，O和P是两个圆的圆心。若两个圆的半径都为r那么阴影部分的面积是多少?
阴影区所构成的四边形的四条边都等于r，所以它可以分成两个边长为r的等边三角形，所以阴影区的面积
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阴影区所构成的四边形的四条边都等于r，所以它可以分成两个边长为r的等边三角形，所以阴影区的面积
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