choose some preferred measures,
say metric measures ...
length: centimetres (cm),
area: square centimetres (cm^2),
volume: cubic centimetres (cc),
weight: grams (gm),
value: dollars ($),
density (gm/cc)
-
look up the relevant conversion factors
1 ft = 1 foot = 30.48 centimeters
1 µm = 1 micro metre = 10-6 metres = (10^-6 x 10^2) cm = 10^-4 cm
1 mL = = 1 millilitre = 1 cc
-
given to your preferred measures, convert values ...
surface area:
1 ft^2 = (30.48^2) cm^2
statue surface area =
13.1 ft^2 =
(13.1*(30.48^2)) cm^2
-
gold thickness =
1.09 µm = 1.09 micrometres = (1.09*10^-6) metres = (1.09*10-6*10^2) cm = (1.09*10-4) cm
-
volume of gold needed =
statue surface area * desired gold thickness =
((13.1*(30.48^2)) * (1.09*10^-4)) cc
-
density of gold = 19.3 g/mL = 19.3 g/cc
-
weight of gold needed =
volume of gold * density of gold =
(((13.1*(30.48^2)) * (1.09*10^-4)) * 19.3) gm
-
price of gold = $625.10 per troy ounce
1 troy once = 31.1035 gm
so, 31.1035 gm gold costs $625.10
so 1 gm gold costs $(625.10/31.1035)
-
cost of gold for statue (in $'s) =
weight of gold (in grams) * price of gold (in $ per gram) =
(((((13.1*(30.48^2)) * (1.09*10^-4)) * 19.3))*(625.10/31.1035)) =
514.5472541778497210924815535229154275242336071503207034578102142847
$514.55 ?
