The density of silver is ρ = 10500 kg/m³ approximately.
Given:
m = 1.70 kg, the mass of silver
t = 3.0 x 10⁻⁷ m, the thickness of the sheet
Let A be the area.
Then, by definition,
m = (t*A)*ρ
Therefore
A = m/(t*ρ)
= (1.7 kg)/ [(3.0 x 10⁻⁷ m)*(10500 kg/m³)]
= 539.7 m²
Answer: 539.7 m²