Electric field physic 2 please show all the steps

Question

The electric field between the plates of a paper-separated (K=3.75) capacitor is 8.21×104 V/m . The plates are 1.75 mm apart, and the charge on each plate is 0.690 μC .Determine the area of each plate.

Answer 1

You know C = κε₀A/d , V = Ed, and Q/V = C (The only thing you don't know is A)

Q/(Ed) = κε₀A/d

A = Q/(Eκε₀) Sub in. Make sure d is in meters and Q in Coulombs and you will get area in m²

Take care.