Given a 10 foot length of tree trunk with a radius of 3 feet, what is the weight of the tree trunk section if it has a density of 45 lb/ft3? (to the nearest whole integer)

The answer is  12,723 lb

Use the formula for the volume of a cylinder to model the volume of the tree trunk.

V = πr^2h
V = π(3^2)(10)
V = 90π ft^3 

therefore,

90π ft^3 × 45 lb/ft^3 = 12723.4502