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

Home > Shapes > Geometry
Two ladders (Posted on 2013-03-12) Difficulty: 3 of 5
Given two crossed ladders resting against two parallel walls.
The feet of the ladders are each at the base of the opposite wall.

Denote the height at which they cross by h and the lengths of the ladders by m and n.

1. Find the heights (h1,h2) at which the ladders touch the walls.
2. Show that 2*h is the harmonic average of h1 and h2.
3. Evaluate the distance (D) between the walls.
4. Provide an example such that m,n,h,h1,h2 and D are integers.

No Solution Yet Submitted by Ady TZIDON    
No Rating

Comments: ( Back to comment list | You must be logged in to post comments.)
Some Thoughts Thoughts Comment 1 of 1
1.  These follow from the Pythagorean Theorem. h1=sqrt(m^2-D^2) and h2=sqrt(n^2-D^2)

2. A very interesting finding, which I suspect is generalizable to all trapezoids. (No proof yet)

3. Part 2 implies that the ratio of h1:h2:h is independent of D.  That fact I have seen used in another puzzle (but I cannot seem to find it.)

4. I assume you want something nontrivial: m!=n.  Then I have m=119, n=70, h=30, h1=105, h2=42, D=56

Edited on January 1, 2017, 9:19 am
  Posted by Brian Smith on 2017-01-01 00:32:22

Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (1)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (14)
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