What is the meaning of Radian?

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In the International System of Units, the derived unit of plane angular measure of angle equal to the angle subtended at the centre of a circle by an arc of its circumference equal in length to the radius of the circle. Symbol: rad.

radian

radian

radian

radian

third-person plural present indicative of radiar

a radian, an angular measure where pi radians = 180°

Source: wiktionary.org