radian
radian — noun
- radiansingular
- radiansplural
1. a unit for measuring angles in mathematics and physics, based on the radius of a
a unit for measuring angles in mathematics and physics, based on the radius of a circle. One radian is the angle size you get when the arc (the curved part of the circle's edge) and the radius that reaches out from the centre are the same length. A full circle contains about 6.283 (2π) radians.
Talia set her calculator to radians before working on the trigonometry problems.
collocation: set [calculator] to radians
A full circle measures 2π radians, which is equal to 360 degrees.
conversion: radians ↔ degrees
Professor Asher asked the class to convert 45 degrees into radians for the exercise.
The engineering formula uses radians, so Salma had to switch her calculator mode before starting.
When the arc length equals the circle's radius, the angle formed is exactly one radian.
用法筆記
Most scientific calculators have a 'RAD' or 'rad' mode for angle input. Many mathematical formulas, especially in calculus and physics, naturally work best with radians rather than degrees.