A catchment may be idealized as a circle of radius $30 \mathrm{~km}$. There are five rain gauges, one at the center of the catchment and four on the boundary (equi-spaced), as shown in the figure (not to scale).
The annual rainfall recorded at these gauges in a particular year are given below.
$\begin{array}{|l|l|l|l|l|l|}
\hline \text{Gauge} & \mathrm{G}_1 & \mathrm{G}_2 & \mathrm{G}_3 & \mathrm{G}_4 & \mathrm{G}_5 \\
\hline (\mathrm{Rainfall ~ mm}) & 910 & 930 & 925 & 895 & 905 \\\hline\end{array}$
Using the Thiessen polygon method, what is the average rainfall (in $\text{mm,}$ rounded off to two decimal places) over the catchment in that year?___________
