Question

One cubic foot of sand weighs about 100 pounds. Approximate the weight of the cone-shaped pile of sand. Round your answer to the nearest hundred pounds.

Answer 1

To find the weight of this sand you will use the formula for finding the volume of a cone and then multiply this by 100.  The volume will give us the number of cubic feet.

V = 1/3 x B x h (B is the area of the circle)
V = 1/3 x (pi x r^2) x h
      1/3 x 3.14 x 3.75^2 x 4.5
V = 66.23 cubic feet

66 cubic feet x 100 = 6600 pounds

The sand weighs approximately 6600 pounds.