For this case we have the following equation: S = 0.159 + 0.118logD Substituting S = 0.2 we have: 0.2 = 0.159 + 0.118logD From here, we clear the value of D. We have then: 0.2 - 0.159 = 0.118logD logD = (0.2 - 0.159) / (0.118) logD = 0.347457627 10 ^ (logD) = 10 ^ 0.347457627 D = 10 ^ (0.347457627) D = 2.23 mm Answer: The average diameter, D, of the sand particles for a beach is: D = 2.23 mm
