问题 选择题

把菱形绕它的中心旋转,使它与原来的菱形重合,那么旋转的角度至少是(  )

A.90°

B.180°

C.270°

D.360°

答案

∵菱形是中心对称图形,

∴把菱形绕它的中心旋转,使它与原来的菱形重合,旋转角为180°的整数倍,

∴旋转角至少是180°.

故选B.

完形填空
完形填空。
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单项选择题