The worksheet allows teachers and student to test different values for polygon sides and be able to compare the approximations of Pi between Archimedes' ad Snell-Huygens' methods. By inserting the numbers in the Input Box beside the number of sides caption, we can change the values of n starting with 6 and double it until 96. The corresponding numbers of n (= number of polygon sides), P_L (= Archimedes' lower limit of Pi), P_U (= Archimedes' upper limit of Pi), A_p (= average of P_L and P_U), and S_p (= Approximation of Pi by Snell-Huygens) will appear in the spreadsheet automatically The results showed that, when compared to Archimedes’ process, the Snell-Huygens’ method improves the approximation of Pi significantly with the same number of polygon sides.