Answer: 5 m²
Step-by-step explanation:
[tex]Remember:\\\\\boxed{p=\dfrac{F}{S} }\\\\\\\\where\ p\ is \ the\ pressure\ (in\ pascal=1N/m^2)\\\\F\ is \ the \force\ (in\ N)\\\\S\ is \ the\ area\ (in \m^2)\\\\S=\dfrac{F}{p} =\dfrac{400\ N}{80\ N/m^2} =5\ m^2\\[/tex]
