A flat, rectangular sheet of gold foil measures 20 cm by 20 cm and has a mass of 23.16 grams. If 1 cubic centimeter of gold has a mas of 19.3 grams, find the thickness of the gold foil.
As a ratio:
(20 cm * 20 cm * x) / 23.16 gm = 1 cm^3 /19.3 gm
Solve for 'x'
x = ( 1 * 23.16)/(19.3 * 20 * 20) = .003 cm thick