radian

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radian

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

radian

(ray -dee-ăn) A unit of angle used in plane geometry that is the angle subtended at the center of a circle by an arc of the circle equal in length to the circle's radius. Thus 2π radians equals 360°, 1 radian equals 57°.296, and 1° equals 0.017 radians. Solid angles, used in spherical geometry, are measured in steradians.

Radian

 

the central angle subtended in a circle by an arc whose length is equal to the circle’s radius. A radian is approximately equal to 57°17′44.8″. The radian is used as the unit of measurement of angles in what is known as circular, or radian, measure. If the circular measure of an angle is a radians, the angle contains (180a/π)°. Conversely, if the degree measure of an angle is , the circular measure is πn/180 radians. For example, angles of 30°, 45°, 60°, 90°, and 180° correspond to angles of π/6, π/4, π/3, π/2, and π radians, respectively.

radian

[′rād·ē·ən]
(mathematics)
The central angle of a circle determined by two radii and an arc joining them, all of the same length.

radian

The angle subtended at the center of a circle by an arc equal in length to its radius. A radian is an SI (Système international d'unités, or international system) unit most commonly used in sight calculations and other aiming problems. Its short form is rad, and its value is equal to 57°17'44.8”, or one rad = 57.2958°.