PART II: Trapezoidal Rule and Simpson's 1/3 rd Rule in finding approximate volume To promote the sales, an artificial waterway or canal needs to be constructed to the Leisure Centre from a nearby Lake. A canal of length (a+900)unit (similar to the Fig 4.) will be constructed to join the Leisure Centre and the lake, on the side b of the quadrilateral. The nine cross sectional areas of the trench at regular intervals are: 500, 550, 600, 610, 625, 630, 645, 650 and 655units2. Figure 4