The round hay bale is 4 feet long and has a diameter of 6 feet, what is the square footage?

Question

The round hay bale is 4 feet long and has a diameter of 6 feet.  the square hay bale has a width of 2 feet, height of 1.5 feet, and a length of 3 feet.

 

Approximately how many square bales would you need to purchase to have the same amount of hay as one round bale?  Based on this result, do you think its better to buy square bales or round bales?  Why?

 

You need 16,000 sq ft of hay to last through the year, Determine how many of each hay bale you would need to purchase if you purchase either all square bales or all round bales.  If one round bale costs $20 and one square bale costs $2.75, which would be the better value?

Answer 1

For this problem, you'll need to use the formulas for the volume of a cylinder and a rectangular prism (it seems as though the question should be in cubic feet rather than square feet since they are 3-dimensional objects).  

 

Round hay bale (cylinder): radius=diameter/2=3

V= πr² X h = π(3)² X 4 = 36π ft³ which is about 113 ft³

 

Square hay bale (rectangular prism):

V= LXWXH = 3X2X1.5 = 9 ft³

 

To find how many square bales to purchase, divide the number of cubic feet in a round hay bale by the number in a square hay bale:

113/9 = 12.56 (round up 0.01)

 

To find how many bales to purchase for each kind, divide 16,000 by the number of cubic feet in each kind of bale (113 and 9). Then to decide which to purchase, multiply the number of round hay bales you would need by $20 and the number of square bales you would need by $2.75. Your answer is which price comes out cheaper!