Is it possible to cut a square of side $1$ into two parts and rearrange them so that one can cover a circle having diameter greater than $1$? (Note: any circle with diameter greater than $1$ suffices) (A. Shapovalov) (Translated from here.)
Problem
Source: Tournament of Towns 2016 Fall Tour, A Senior, Problem #5
Tags: combinatorial geometry, geometry, combinatorics
22.04.2017 22:00
Should it be "circle having diameter greater than $1$" or "square of side $2$"
22.04.2017 22:04
Sorry. Fixed. Edit: @below, I am not sure, I'll have to check .
23.04.2017 07:52
Can the two pieces intersect?
23.04.2017 08:56
just to make sure, is it necessary for the cut to be a straight line?
23.04.2017 18:37
I think the cut doesn't need to be a straight line. If it does, then certainly the answer will be no.
23.04.2017 19:24
It should be read as: Is it possible to partition a square of side $1$ into two parts and cover with them a circle having diameter greater than $1$? That's: yes, they can overlap and we don't impose the square to be cut by a straight line, just to be presented as a union of two non-intersecting sets.
23.04.2017 19:31
msinghal and I were working on the problem with the added restriction that the pieces cannot overlap, but all promising constructions have yielded a maximum circle size of diameter 1... any ideas here?
23.04.2017 20:03
bobthesmartypants wrote: ...aim to use some extra pieces from the corners to cover an extra epsilon near the middle of two adjacent sides of the square So, as I see the parts in that construction don't overlap. In fact the given by the author solution is actually the same.
23.04.2017 20:14
dgrozev wrote: bobthesmartypants wrote: ...aim to use some extra pieces from the corners to cover an extra epsilon near the middle of two adjacent sides of the square So, as I see the parts in that construction don't overlap. In fact the given by the author solution is actually the same. Can you please give a drawing?
23.04.2017 22:34
Ok, open this pdf document: http://sasja.shap.homedns.org/Turniry/TG/38os.pdf go at the 6-th page- at the bottom, look at the right drawing. The two red triangles are cut off and go to the place where the green ones are. Or simpler, one can cut off the four corners and glue them at the middle of the four sides of the square.
23.04.2017 23:10
dgrozev wrote: Ok, open this pdf document: http://sasja.shap.homedns.org/Turniry/TG/38os.pdf go at the 6-th page- at the bottom, look at the right drawing. The two red triangles are cut off and go to the place where the green ones are. Or simpler, one can cut off the four corners and glue them at the middle of the four sides of the square. Oh, but they do overlap: the skinny green strip of one piece overlaps with the other piece. It's a much harder problem to not have any overlaps at all.
23.04.2017 23:31
I thought the english word "overlap" meant they had a common interior point. In that case they touches each other, that's they have only common points on their contours. If you want the two parts to be isolated from each other, it's impossible.
23.04.2017 23:35
But there's a common interior point in the red circled region:
23.04.2017 23:48
Come on, don't be so punctual. As I said, just cut off a small piece of every corner and glue them at the middle of the four sides of the square(at their outer sides). The problem is not so smart as you think.
23.04.2017 23:49
But then you don't have two connected pieces, you have 5...
18.02.2022 00:21
Can someone share some idea how to solve the problem or tell where I can (if possible) see the official solution?