In Exercises 19-21 use Green's Theorem to find the area A of the given region. 19. The region bounded below by the x axis and above by one arch of the cycloid parametrized by r(t) = (t − sin t)i + (1 - cost)j for 0 ≤t≤2π (Hint: To obtain the area of the region you must use the correct orientation of the boundary.)