A circle sector OAB has angle 0.8 radians. What is arc length AB?
A circle is 2π radians.
So the angle measure is 0.8/2π = 0.4/π part of the circle.
The circle has circumference 2π20 = 40π
We multiply 0.4/π by 40π to get the length AB, so thus (0.4 * 40π)/(π) = 16π/π = 16
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