注目コメント算出アルゴリズムの一部にLINEヤフー株式会社の「建設的コメント順位付けモデルAPI」を使用しています
The radian, denoted by the symbol rad, is the unit of angle in the International System of Units ... The radian, denoted by the symbol rad, is the unit of angle in the International System of Units (SI) and is the standard unit of angular measure used in many areas of mathematics. It is defined such that one radian is the angle subtended at the centre of a circle by an arc that is equal in length to the radius.[2] The unit was formerly an SI supplementary unit and is currently a dimensionless SI
2011/09/24 リンク