To find the length of an arc of a circle, we use the formula:
Arc length = (central angle/360°) x 2πr
where r is the radius of the circle.
In this case, the central angle is 20°, and the radius is 10 ft. So we can plug in these values and simplify:
Arc length = (20/360) x 2π(10)
Arc length = (1/18) x 20π
Arc length = 10/9 π or approximately 3.49 ft.
Therefore, the length of a 20° arc for a circle with a 10 ft. radius is approximately 3.49 feet.