Chapter 9.4, Problem 26E

Area To determine the amount of water flowing down a certain $100\text{-}$ yard-wide river, engineers need to now the area of a vertical cross section of the river. Measurements of the depth of the river were made every $20$ yard from one bank to the other. The readings in fathoms were $0,1,2,3,1,0.$(one fathom equals $2$ yards.) Use the trapezoidal rule to estimate the area of the cross section.