# Radian

[rey-dee-uh n] /ˈreɪ di ən/

**noun**, Mathematics.

1.

the measure of a central angle subtending an arc equal in length to the : equal to 57.2958°.

Abbreviation: rad.

/ˈreɪdɪən/

**noun**

1.

an SI unit of plane angle; the angle between two radii of a circle that cut off on the circumference an arc equal in length to the radius. 1 radian is equivalent to 57.296 degrees and π/2 radians equals a right angle rad

n.

“angle subtended at the center of a circle by an arc equal in length to the radius,” 1879, from radius.

radian ra·di·an (rā’dē-ən)

n.

Abbr. rad

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.

radian

(rā’dē-ən)

A supplementary unit of the International System used in angular measure. One radian is 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°17’44.6″.

Tagged: r

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