- -0+00- 1+00_ 1+40_ 2 +00 2+40 3+00 Solution 1) Change in slope = 1 -10 = - 9o (Slope Reduced by 9o) 2) Change in elevation from Station 0+00 to1+40 = tan (Angle) * Horizontal distance = (tan 10) *140 = 24.685 feet 3) Length of pipe rom Station 0+00 to1+40 = Horizontal Distance / [Cos (angle)] = 140 / [cos 10] = 142.159 feet.