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

Home > Shapes > Geometry
Square in a Pentagon (Posted on 2013-12-01) Difficulty: 3 of 5
What is the size of the largest square which can fit inside a regular pentagon with a side-length of 1?

No Solution Yet Submitted by Danish Ahmed Khan    
Rating: 3.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
re(2): More likely to be correct solution. Comment 4 of 4 |
(In reply to re: More likely to be correct solution. by Jer)

I agree.

Construction: Construct pentagon ABCDE with centre O. Construct a line perpendicular to AO and bisect both angles to AO with lines passing through BC at F and DE at H, to form 2 sides of the square. Lines perpendicular to AF and AH will meet at G to complete the square AFGH.

The area of the square is 5-5^(1/2)-(5 (5-2*5^(1/2)))^(1/2). The ratio of the pentagon to the square is (5^(1/2)+(2*(5+5^(1/2)))^(1/2))/4 to 1, almost exactly 1.51 times the size.

Edited on December 3, 2013, 6:32 am
  Posted by broll on 2013-12-03 06:27:14

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 (4)
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