Where Do Points Sum to Two-Thirds the Perimeter of a Rectangle?

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Discussion Overview

The discussion revolves around the geometric problem of identifying the set of points outside a rectangle ABCD where the sum of the distances from these points to the rectangle's sides equals two-thirds of the rectangle's perimeter. The scope includes exploratory reasoning and geometric modeling.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant proposes identifying the set of points X such that the sum of the distances from X to the sides of the rectangle equals two-thirds of the perimeter.
  • Another participant clarifies that the distances are the lengths of perpendiculars dropped from point X to the sides of the rectangle.
  • A participant suggests that if point X lies inside the rectangle, the sum of distances would equal half the perimeter, indicating that the locus cannot include points inside the rectangle.
  • There is a hypothesis that the answer may be an octagon, although this is not confirmed through explicit calculations.
  • One participant suggests dividing the exterior of the rectangle into eight sections to find equations for each section, implying a method to approach the problem.

Areas of Agreement / Disagreement

Participants express uncertainty about the exact solution, with some suggesting the answer may be an octagon while others propose methods to explore the problem further. No consensus is reached on the solution or the approach.

Contextual Notes

The discussion does not resolve the mathematical steps required to arrive at the solution, and assumptions about the nature of the points and their locations are not fully articulated.

Numeriprimi
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I found one interesting example...

We have a rectangle ABCD with his perimeter o. Where is the set of points when their (for each point) sum of distance lines AB, BC, CD, DA is 2/3o ?

I tried it, but geometric problems is quite hard for me and I don't know how do it. So, have you got any idea?
 
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Numeriprimi said:
Where is the set of points when their (for each point) sum of distance lines AB, BC, CD, DA is 2/3o ?

Sorry, Numeriprimi, I don't understand. :confused:
 
I think the problem is to identify the set of points X such that
d(X,AB)+d(X,BC)+d(X,CD)+d(X,DA)= \frac{2}{3}*\text{Perimeter of Rectangle ABCD}.
The distances on the left hand side are lengths of perpendiculars dropped from the point X to the corresponding line. For example, if X lies inside the interior, then the left hand side would equal (1/2) the perimeter. So the locus cannot include points inside the rectangle. Without doing an explicit calculation, I bet the answer is an octogon.
 
Sorry for my English... And Vargo, yes, I mean this, thanks for wrote it in better form :-)
 
Thanks, Vargo! :smile:

Numeriprimi, divide the exterior of the rectangle into 8 sections (by extending the sides),

and consider each section separately …

you should be able to find an easy equation for each section. :wink:

(and yes, it's an octagon!)
 

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