The yield strength for an alloy that has an average grain diameter of $5\mathrm{.}3{10}^{-2}mm$ is $132$MPa. At a grain diameter of $7\mathrm{.}3{10}^{-3}mm,$ the yield strength increases to $263$MPa. At what grain diameter, in mm$,$ will the yield strength be $223$MPa $?$

$d=$

$mm$