Current Attempt in Progress

$($Force on plane surface$)$ The rectangular gate CD of the figure below is $1\mathrm{.}9$ m wide and $2\mathrm{.}0$ m long. Assuming the material of the gate to

be homogeneous and neglecting friction at the hinge C$,$ determine the weight of the gate necessary to keep it shut until the water level

rises to $2\mathrm{.}2$ m above the hinge.