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

Home > Shapes
Half Squared (Posted on 2004-04-08) Difficulty: 1 of 5
Given a square piece of paper, show how by creasing and folding only, a square of half the area of the original can be obtained.

See The Solution Submitted by Richard    
Rating: 3.2000 (5 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
re: Variation: | Comment 4 of 13 |
(In reply to Variation: by Gamer)

This is going to be hard to explain with out diagrams, but here goes:

Take original square ABCD (AB = length 1 and AC = length 2)
1. Fold and unfold the diagonal AC.
2. Fold AB onto AC (B lies on AC.)
3. Fold AD onto AC (D lies on AC too.)
4. Fold C onto A.
5. Unfold steps 2, 3, and 4.
There is now a crease from B to D. Call the point where it crosses AC 'O'. Call the small creases perpendicular to AB and AD 'X' and 'Y' respectively. AO = AX = AY = .52.
6. Fold DC up so that D is on AY and C is on BC.
Call the new bottom corner across from Y and below B 'Z'.
7. Fold BZ over so that B is on AX and Z is on ZY.

AXZY is the required square.

This takes 6 folds. I'm not sure if it can be improved.

-Jer

(I recommend you actually try this. It will probably make more sense if you do.)

ps. The fold in step 3 is not strictly needed, so this is 5 folds.
Edited on April 8, 2004, 9:59 am
  Posted by Jer on 2004-04-08 09:52:16

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