Amarble pillar in the shape of a square prism has a length and width of 2.5 feet and a height of 12 feet. the pillar weighs 12,000 pounds. how many pounds per cubic foot is the density of the marble?

Density is a property of a material which describes the mass of a material per unit volume. We calculate as follows:

Density = mass / volume

mass = 12000 lbs
volume = lwh = (2.5)(2.5)(12) = 75 ft^3

Density = 12000 / 75 = 160 lbs/ft^3 

Equatorial triangle and obtuce angle