Question 336925
you need to find the volume of the lake in milliliters
___ a mL is equal to a cubic centimeter (cc or cm^3)


the volume of the lake is the surface area multiplied by the depth


5280 ft in a mile
12 inches in a foot
2.54 cm in an inch


the number of mL in the lake is ___ 100 mi^2 * (5280 ft/mi)^2 * 20 ft * (12 in/ft)^3 * (2.54 cm/in)^3


the number of mL should be multiplied by  .4 µg/mL (4x10^-7 g/mL)
___ this will give the number of grams , which you can convert to kg (divide by 10^3)