Answer:
15π/2 ft
Explanation:
Arc length is given by the formula ...
s = rθ . . . . . r = radius; θ = central angle in radians
A 135° arc has a radian measure of (135)(π/180) = 3π/4. The radius of a circle with a 20 ft diameter is (20 ft/2) = 10 ft. So, the arc length is ...
s = (10 ft)(3π/4) = 30π/4 ft = 15π/2 ft