弧度 Radian

（重定向自Radian measure）

弧度又称弪度，是平面角的单位，也是国际单位制导出单位。单位弧度定义为圆弧长度等于半径时的圆心角。角度以弧度给出时，通常不写弧度单位，或有时记为rad（㎭）。平面角和立体角皆无因次。

一个完整的圆的弧度是2π，所以2π rad = 360°，1 π rad = 180°，1°=π/180 rad，1 rad = 180°/π（约57.29577951°）。以度数表示的角度，把数字乘以π/180便转换成弧度；以弧度表示的角度，乘以180/π便转换成度数。

同样地︰

微积分的三角函数中，角度以弧度为单位，以获得简洁的结果。例如以弧度为单位，有如下简单等式：

单词	Radian measure
释义	Radian measure 中文百科弧度 Radian （重定向自Radian measure）弧度又称弪度，是平面角的单位，也是国际单位制导出单位。单位弧度定义为圆弧长度等于半径时的圆心角。角度以弧度给出时，通常不写弧度单位，或有时记为rad（㎭）。平面角和立体角皆无因次。一个完整的圆的弧度是2π，所以2π rad = 360°，1 π rad = 180°，1°=π/180 rad，1 rad = 180°/π（约57.29577951°）。以度数表示的角度，把数字乘以π/180便转换成弧度；以弧度表示的角度，乘以180/π便转换成度数。同样地︰微积分的三角函数中，角度以弧度为单位，以获得简洁的结果。例如以弧度为单位，有如下简单等式：英语百科 Radian 弧度（重定向自Radian measure） The radian is the standard unit of angular measure, used in many areas of mathematics. An angle's measurement in radians is numerically equal to the length of a corresponding arc of a unit circle; one radian is just under 57.3 degrees (when the arc length is equal to the radius; expansion at A072097). The unit was formerly an SI supplementary unit, but this category was abolished in 1995 and the radian is now considered an SI derived unit.
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Radian measure

弧度 Radian

Radian 弧度