Zinc has a density of 0.258 lb/in³ (pounds per cubic inch).
Darius is making a pyramid out of solid zinc. The pyramid has a square base 5 inches on each side, and a height of 3.3 inches.
How many pounds of zinc does he need?
Show all your work. Do not round the final answer.
Have a look at http://mdk12.msde.maryland.gov/instruction/curriculum/hsa/geometry/math_reference_sheet.html to see the formulae for calculating the volume of various shapes (including a square based pyramid).
For this question note that mass = density*volume.
ok. Volume of square based pyramid is V = (1/3)*base area*height
Here base area = 5^2 in2
height = 3.3"
Hence V = (1/3)*25*3.3 in3
So mass = V*density = (1/3)*25*3.3 in3 * 0.258 lb/in3 → (1/3)*25*3.3*0.258 lb
I'll leave you to do the multiplication.