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- A plane figure bounded by two radii and the included arc of a circle. 由两个半径和两个半径中间的弧所形成的一个平面形状。
- A radian is the angle subtended by an arc of a circle whose length is just equal to the radius. 一弧度就是长度刚好等于半径的一段圆弧所对的圆心角。
- The axis of a circle is its diameter. 圆的轴线是其直径。
- The reciprocal of the radius of a circle. 曲率一个圆半径的倒数
- The diameter and the circumference of a circle. 圆的直径和圆周相关联。
- Tell the names of each part of a circle. 说出圆各部分的名称。
- He should have been the sun of a circle. 他本应该做一个周而复始的太阳。
- Almost all the balls follow the shape of a circle. 几乎所有球类都呈圆形。
- Circumference:The boundary line of a circle. 圆周:一个圆的边界线.
- A diameter passes through the center of a circle. 直径从圆心穿过。
- Teacher: What is the perimeter of a circle? 师：什么是圆的周长?
- Any two diameters of a circle intersect each other. 圆周内两直径必相交。
- An arc is a part of the circumference of a circle or other curved lines. 弧是圆周或曲线的一部分。
- Now he twisted himself into a circle, then stretched himself out on the ground like the trunk of a fallen tree. 它先把身子缩成一团，然后又申长，活象一截伐倒在地的树桩。
- "Because a straight line can be thought of as an arc of a circle of infinite radius, its curvature is zero." 直线可视为半径无穷大的圆，曲率为0
- A radian is the angle subtended by an arc of a circle whose length is just equal to the radius 一弧度就是长度刚好等于半径的一段圆弧所对的圆心角。
- A circular arc of90=; one fourth of the circumference of a circle. 九十度弧；圆周的四分之一
- An arc is a part of the circumference of a circle or other curved line. 弧是圆周或曲线的一部分。
- The diameter and the circumference of a circle correlate. 圆的直径与圆周有相互关系。
- The area bounded by a chord and the arc of a curve subtended by the chord. 弓形,扇形由弦正对的弦和弧线的弧所成的区域。
