a$.$ A shear box test carried out on a soil sample gave the following results

$\backslash$table$[[$Vertical load $[$kg$],36\mathrm{.}8,73\mathrm{.}6,110\mathrm{.}4,147\mathrm{.}2],[\backslash$table$[[$Gauge reading for proving$],[($shearing$)$ ring $m$