Question #23b0f

1 Answer
Oct 21, 2015

This is a volume problem using a truncated cone .

Explanation:

If you invert the flower pot upside down, you get a truncated cone:

enter image source here

The solution to the problem is to find the volume of the outer cone then subtract the volume of the inner cone.

The difference between the two cones is the 3 inch thick uniform wall.

There is a formula for the volume of a truncated cone:

V = 1/3pih(r_1^2+r_2^2+r_1*r_2)

Source: http://keisan.casio.com/exec/system/1223372110

Where, r_1=radius of bottom and r_2=radius of top

Volume of outer truncated cone:

V = 1/3pi12(9^2+6^2+9*6)=2148.849375 cu in

Volume of inner truncated cone (subtract the 3" wall from each dimension):

V = 1/3pi9(6^2+3^2+6*3)=593.7610115 cu in

Volume of material (one pot) :
V=2,148.849375-593.7610115=1555.0883635 cu in

Finally, Volume of 1000 pots :

Answer =1000*1555.0883635=1,555,088 cu in
~~900 cubic feet of material

Hope that helped