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如图,在边长为1的正方形组成的网格中,△AOB的顶点均在格点上,点A、B的坐标分别是A(3,2)、B(1,3).△AOB绕点O逆时针旋转90°后得到△A
1OB
1.(直接填写答案)
(1)点A关于点O中心对称的点的坐标为______;
(2)点A
1的坐标为______;
(3)在旋转过程中,点B经过的路径为弧BB
1,那么弧BB
1的长为______
考点分析:
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