Check the picture below.
since they're similar figures
[tex]\cfrac{12^2}{8^2}~~ = ~~\cfrac{696}{A}\implies \cfrac{144}{64}~~ = ~~\cfrac{696}{A}\implies \cfrac{9}{4}=\cfrac{696}{A}\implies 9A=2784 \\\\\\ A=\cfrac{2784}{9}\implies A=\cfrac{928}{3}\implies A=309\frac{1}{3}[/tex]