The rectangles in the figure below illustrate a right endpoint Riemann sum for f(z) The value of this right endpoint Riemann sum is , the z-axis, and the vertical lines z=2 and r = 6. 8 == on the interval [2, 6]. , and this Riemann sum is greater than the area of the region enclosed by y = f(z) 1 2 3 5 6 7 8 Right endpoint Riemann sum for y = on [2,6] x