Hi, how do you estimate particle size ?

The picture below shows the powder collected on a sieve with an opening size of 90m. The particle size of the powder is not 90m. Provide a best estimate of the particle size of the powder and support your answer with the relevant calculation made. \begin{tabular}{|c|c|c|c|} \cline { 2 - 4 } \multicolumn{1}{c|}{} & \multicolumn{3}{c|}{ Mass of Powder collected on Sieve Tray (g)} \\ \hline Sieve (m) & Run 1 & Run 2 & Run 3 \\ \hline Largest sieve size & 0.06 & 0.07 & 0.07 \\ \hline? & 0.15 & 0.14 & 0.15 \\ \hline? & 0.85 & 0.85 & 0.84 \\ \hline? & 8.64 & 8.70 & 8.65 \\ \hline Smallest sieve size & 9.05 & 9.10 & 9.08 \\ \hline Collection Tray & 11.23 & 11.15 & 11.20 \\ \hline \end{tabular}