trig
posted by Abigail .
If an angle is 1 radian, what is the arc length in radians?

arc length is not measured in "radians", but rather in linear units
if the angle is 1 radian, then the arclength supported by that 1 radian is 1 radius..
arclength = (radius)*(angle in radians)
BTW, that is the definition of 1 radian angle, the central angle of a sector with radius r and arclength of r.