Inner-radius of a (convex) polygon

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    Convex Polygon
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Discussion Overview

The discussion revolves around the properties of convex polygons, specifically whether every convex polygon has an inner-circle (incircle) and the implications of this for the inner-radius. Participants explore the conditions under which an inner-circle exists and seek to understand the relationship between the sides of a convex N-gon and the inner-radius.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant, NaturePaper, questions whether every convex polygon has an inner-circle and suggests that this may only be true for triangles and regular polygons.
  • Another participant argues that drawing a circle inside a convex polygon does not guarantee that the circle will touch all sides, implying that the concept of an inner-circle may not apply universally.
  • NaturePaper seeks clarification on the existence of an inner-circle for any convex N-gon and requests a formula for the inner-radius in terms of the sides.
  • A participant reiterates that the radius and center of the circle will vary depending on which side is being touched, raising questions about the utility of finding the radius.

Areas of Agreement / Disagreement

Participants express differing views on the existence of an inner-circle for all convex polygons, with some suggesting it is not universally applicable. The discussion remains unresolved regarding the conditions under which an inner-circle exists and the implications for the inner-radius.

Contextual Notes

There is a lack of consensus on the definitions and conditions necessary for a convex polygon to have an inner-circle, as well as the mathematical relationships involved in determining the inner-radius.

NaturePaper
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Hi all,
I want to know whether it is correct that every convex polygon has an inner-circle (& hence an inner-radius). I think it is only possible for triangle and for regular polygon. Am I right?

If there is any convex N-gon having sides a_1,a_2,...,a_N which has an incircle, then what is the formula for the inner-radius in terms of the sides?


Regards,
NaturePaper
 
Mathematics news on Phys.org
If you draw a circle inside the convex polygon, it is not necessary that the circle will touch all the sides.
 
then..??
 
So Radius and center of the circle will differ with respect to the side you wish to touch with the circle. then what is the use of finding radius?
 
@KnowPhysics,
I think I'm missing something.

It is well known that for a triangle with sides a_1, a_2, a_3 there is a (unique) circle inscribed
in the triangle whose radius R is given by some formula involving the sides a_i's.

My question was what about the general situation, i,e for any convex N-gon what will be the situation?

Regards,
NaturePaper
 
i explained already, it is not necessary that the circle will touch all the sides. So Radius and center of the circle will differ with respect to the side you wish to touch with the circle.
 

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