The radius of a cylindrical construction pipe is 2 ft, and its length is 18 ft. Answer the parts below. Make sure that you use the correct units in your answers. If necessary, refer to the list of geometry formulas. (a) Find the exact volume of the pipe. Write your answer in terms of . Exact volume: (b) Using the ALEKS calculator, approximate the volume of the pipe. To do the approximation, use your answer to part (a) and the button on the calculator. Round your answer to the nearest hundredth.Approximate volume: