Find the angle X inside a pentagon with a square

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Discussion Overview

The discussion revolves around finding the angle X inside a pentagon that includes a square. Participants explore the properties of the angles in a pentagon and a square, and how these relate to the geometry of the shapes involved. The scope includes mathematical reasoning and geometric relationships.

Discussion Character

  • Mathematical reasoning
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that the interior angles of a pentagon sum to 540 degrees, suggesting that in a regular pentagon, each angle would be 108 degrees.
  • Another participant questions whether one of the angles in the triangle containing angle X can be determined and asks about the type of triangle involved.
  • Some participants propose that the side of the pentagon and the side of the square appear equal, suggesting it could form an isosceles triangle, but express uncertainty about this observation.
  • One participant calculates that the small angle in the triangle could be derived from the relationship between the angles of the pentagon and the square, arriving at a value of 18 degrees for the small angle.
  • Using the small angle, a calculation is presented to find angle X, leading to a proposed value of 81 degrees, but this is based on earlier assumptions and calculations that may not be universally accepted.

Areas of Agreement / Disagreement

Participants express differing views on the relationships between the angles and sides of the pentagon and square. While some calculations are presented, there is no consensus on the correctness of these calculations or the assumptions made.

Contextual Notes

There are unresolved assumptions regarding the specific dimensions and relationships between the sides of the pentagon and square, as well as the nature of the triangle formed. The discussion does not clarify whether the triangle is indeed isosceles or if the proposed calculations are universally valid.

mathlearn
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If the the question is too small , Please be kind enough to read it from here Question

The interior angles of a pentagon add up to 540 degrees. So thinking that this is a regular pentagon with all 5 sides equal an interior would be 108 degrees.

And speaking of the square All four sides are equal and all 4 angles are 0 degrees.

Could have easily found X if the the side with the angle X (shortest side) was a straight line.It could be said using angles on a straight line add up to 180.

But the line seems to be slanted.

I included the information in a diagram,

Untitledpen.png


Any Ideas on How to begin ?

Many Thanks :)
 
Last edited:
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Hey mathlearn! ;)

Can we already find one of the other angles in the small triangle that contains x?
What kind of triangle is it anyway?
 
It looks like that side of the pentagon and the side of the square are equal at a glance , But don't know whether it's correct. If I'm correct then it would be an isosceles triangle

Then this will be the result

2qcju68.png


Many Thanks :)
 
Last edited:
mathlearn said:
It looks like that side of the pentagon and the side of the square are equal at a glance , But don't know whether it's correct. If I'm correct then it would be an isosceles triangle

Then this will be the result

Many Thanks :)

The sides of the square have the same length.
The sides of the pentagon have the same length.
One side of the square has the same length as the corresponding side of the pentagon.
So yes, those sides are indeed equal. :)

Can we say anything about the small angle in the triangle?
 
As the interior angles of the pentagon add up to 540 degrees. So One angle should be equal to 108 degrees. Correct I guess ?

I like Serena said:
The sides of the square have the same length.

Can we say anything about the small angle in the triangle?

:) Yes the small angle of the triangle would be 108(int. angle of the pentagon)=90(int. angle of the square)-(the small angle)

108-90 =small angle
18 degrees = small angle

2ef8epl.jpg


So 180 (interior angles of a triangle add up to 180 ) = 2x + 18
180 -18 = 2x
162 = 2x
81 = x

Many Thanks :)
 

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