划圆是通过直径片的端点沿圆周轨迹转动，其圆心的位置是固定的原理而实现的。

The end of diameter plate moves along the circumference trace and its circle center is fixed.

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划圆是通过直径片的端点沿圆周轨迹转动，其圆心的位置是固定的原理而实现的。

The end of diameter plate moves along the circumference trace and its circle center is fixed.

youdao