Answer:
6
Step-by-step explanation:
Arc length = radius * central angle
s = rθ
A circle is 2π radians, so 1/3 of that is 2/3 π.
Given that s = 12 and θ = 2/3 π:
12 = r (2/3 π)
r = 18/π
r ≈ 6
