5 ms·For those who prefer a text definition: radians = arc length in a circle with R=1by ivan_ah 13y agoFor those who prefer a text definition: radians = arc length in a circle with R=1judk 13y agoLength of which arc?RogerL 13y agoAn arc with the same length as the radius. This is what the animation illustrates.deleted 13y ago[deleted]morpher 13y agoThe measure of an angle in units of radians is equal to the length of the arc subtending that angle in units of radii.