I don't know how to explain this but for the arc length of a circle A and B like the outer length A and B is it equal to the angle O ?
and also how is " " half the amount of the angle O?
for O I mean the central angle
so is the arc length equal to the central angle
I remember now
For a circle of radius r, the arc length of central angle θ is given by rθ.
For a circle of unit radius (i.e. radius=1), r=1, therefore the arc length equals the central angle.
I hope this confirms what you were enquiring.