Part B $-$ The force on a slanted surface

Now consider a slanted surface of length $L$ under the water shown below $($Figure $4).$ If the depths are $d_1=4\mathrm{.}7m$ and $d_2=6\mathrm{.}3m,$ the

width into the screen is $b=10m,$ and $L=4m,$ what is the magnitude of the resultant force on the slanted sufface?

Express your answer in N to three significant figures.

View Available Hint$($s$)$

$F_R=$NN

MM$==??$