This project shows how to use Riemann sum to approximate the area of a unit disk (actually a quarter of a unit disk). This can be used as an approximation of pi.[br][br]This is the Riemann sum using five equal subintervals of [0,1]. You can pick representative points in each subinterval using the slide bar and construct the corresponding approximating rectangle. The height is computed automatically and the computation of the Riemann sum is carried out in the spreadsheet.