How could I find the Arc Length (Unit Circle) of -60 degrees?

Question

If the Arc Length (Unit Circle) of 0 deg is 0
30 deg = 1 / 6π = π / 6
60 deg = 2 / 6π = π / 3
90 deg = 3 / 6π = π / 2

What would be the arc length for -60 deg?
Thanks for the help!!

Answer 1

-π/3 is 60° measured anti-clockwise instead of clockwise.

So we add 360° (2π): 2π-π/3=6π/3-π/3=5π/3.

Think of a clock face. At 2 o’clock the hands are 60° apart while at 10 o’clock they are 300° apart.