$3\mathrm{.}21$ An experimental rectangular plot of $10km12km$ has five rain gauge stations. Fit a coordinate system to the plot such that the side $10$ km represents the abscissa$.$ The storm rainfall and coordinates of the stations are as follows.

$\backslash$table$[[$Station$,\backslash$table$[[$Station$],[$coordinate$]],\backslash$table$[[$Normal annual$],[$rainfall $(cm)$