Answer: 25.13 (choice B)
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The formula we'll use is
s = r*theta
with
s = unknown arc length
r = radius = diameter/2 = 12/2 = 6 feet
theta = 4pi/3 radians <--- this angle must be in radian mode for the formula to work
Plug those values into the formula and simplify
s = r*theta
s = 6*(4pi/3)
s = 24pi/3
s = 8*pi
s = 8*3.1416
s = 25.1328
s = 25.13
which is approximate and rounded to the nearest hundredth.