ra.di.an
n.Abbr. radMathematics (名词)缩写 rad【数学】 A unit of angular measure equal to the angle subtended at the center of a circle by an arc equal in length to the radius of the circle, approximately 57=7&S{¢}44.'".See table at measurement 弧度:平面角的一种衡量单位,其大小为长度等于半径的弧对的圆心角,弧度角约等于57=7&S{¢}44.'"参见 measurement
来源:radi(us) radi(us)-an -an