ra·di·an /ˈrediən/
弧度
ra·di·an /ˈredɪən/ 名詞
弧度
radian
弧度
radian
弧度 弳
Ra·di·an n. Math. An arc of a circle which is equal to the radius, or the angle measured by such an arc.
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radian
n : the unit of plane angle adopted under the Systeme
International d'Unites; equal to the angle at the center
of a circle subtended by an arc equal in length to the
radius (approximately 57.295 degrees) [syn: rad]