SOLUTION: A post is 11 ft. in length, 9 in. square at the bottom, and 4 in. square at the top. Find amount of board feet. 1 board foot is 1 ft. long, 1 ft. wide, and 1 in. thick. Not

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Question 1130881: A post is 11 ft. in length, 9 in. square at the bottom, and 4 in. square at the top. Find amount of board feet.
1 board foot is 1 ft. long, 1 ft. wide, and 1 in. thick.
Not sure how to solve. Non-homework.
Answer by ikleyn(52781)   (Show Source): You can put this solution on YOUR website!
.
Use the formula for the volume of a frustum of a square pyramid 


V =  


where a and b are the base and top side lengths of the truncated pyramid, and h is the height. 


In your case  a=  = 3 inches;  b=  = 2 inches  and  h = 11 ft = 11*12 = 132 inches.


Do the rest on your own.


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