The arc length is:
S = R * theta
Where,
R: Radio
Theta: central angle
Substituting values we have:
Circle A:
Sa = Ra * (140/360) * 2π
Circle B:
Sb = Rb * (140/360) * 2π
The relationship of arcs is:
Sa / Sb = (Ra * (140/360) * 2π) / (Rb * (140/360) * 2π)
Rewriting:
Sa / Sb = (Ra / Rb)
Substituting values:
(3 / 4π) / Sb = 2/3
Clearing Sb
Sb = (3/2) (3 / 4π)
Sb = (9 / 8π)
Answer:
The length of the intercepted arc for circle B is:
Sb = (9 / 8π)