Given the data points needed to plot the graph. How was area computed?

please explain properly and how 0.233 was solved as the area of the graph.

Wetslabwt,kgRate,kg/m2hr9.14.97.24.95.34.44.23.93.33.42.92.02.71.0 Given: Wws=5kgA=600900mm2X1=0.9474Q=50.5=2.5kgx=75mmX2=0.1238 Wsi:= \begin{tabular}{|l|} \hline 5.3 \\ \hline 4.2 \\ \hline 3.3 \\ \hline 2.9 \\ \hline 2.7 \\ \hline \end{tabular} Ri1= \begin{tabular}{|r|} \hline 0.22727 \\ \hline 0.25641 \\ \hline 0.29412 \\ \hline 0.5 \\ \hline 1 \\ \hline \end{tabular}