A 40 foot tall building r feet from an observer subtends an angle of 4º

Question

Use the arc length formula to estimate r (the distance between the observer and the building) to the nearest foot.

r ≈ ?

Answer 1

s = rθ, where s is the arc length, r is the radius, and θ is the angle in radians.

40° ≈ 0.6981317008 rad

s (what the problem calls "r") = (40)(0.6981317008 rad)