All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > General
Pile of Cannonballs (Posted on 2004-08-03) Difficulty: 3 of 5
If one stacks 10 cannonballs of diameter d in a pile (tetrahedron), what is the height of the pile?

No Solution Yet Submitted by ThoughtProvoker    
Rating: 3.0000 (2 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
re: solution | Comment 10 of 12 |
(In reply to solution by Lorne Hrynkiw)

You write "This triangle has a hypotenuse of 2d and the length the horizontal side is d; thus the remaining side is d*sqrt(3)." But this triangle is a (slanting) face of the tetrahedron with side length 2d, and its height is slanting, too.  We need instead the vertical height of that tetrahedron, which is the slightly smaller value 2d*sqrt(2/3)=(2d/3)*sqrt(6)=1.632993162d. See, e. g.,

http://mathforum.org/library/drmath/view/55009.html


  Posted by Richard on 2004-08-05 00:35:59
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (12)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2024 by Animus Pactum Consulting. All rights reserved. Privacy Information