Couple geometry/trigonometry questions

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Discussion Overview

The discussion revolves around geometry and trigonometry questions from Gelfand's Trigonometry, specifically focusing on the properties of circles related to triangles. Participants explore the implications of a triangle's hypotenuse being the diameter of a circle and seek solutions to specific problems presented in the text.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether the hypotenuse of any right triangle inscribed within a circle must be the diameter, expressing uncertainty about how to solve the related problem.
  • Another participant asserts that if the diameter of a circle is the hypotenuse of a triangle, then that triangle is indeed a right triangle, implying that the hypotenuse must be the diameter.
  • A later reply elaborates on the reasoning behind the assertion that the hypotenuse must be the diameter, suggesting that if it were not, it would lead to contradictions regarding the triangle's properties.
  • One participant initially misinterprets the question regarding circles and triangles, suggesting that the author may have meant a circle inscribed in a triangle instead of one passing through the vertices.
  • Another participant corrects their earlier misquote of the question, clarifying that it pertains to a circle drawn through the vertices of a triangle.

Areas of Agreement / Disagreement

There is some agreement on the relationship between the hypotenuse and the diameter of a circle, but there is also confusion regarding the interpretation of the original question about circles and triangles. Multiple competing views remain about the nature of the circle referenced in the problem.

Contextual Notes

Participants express uncertainty about the correct interpretation of the question and the existence of solutions to the problems posed in Gelfand's Trigonometry. The discussion reflects varying understandings of geometric principles and terminology.

Velcroe
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I am reading Gelfand's Trigonometry. In one of the questions he asks: "We know from geometry that a circle may be drawn through the three vertices of any triangle. Find the radius of such a circle if the sides of the triangle are 6,8, and 10."

My first question is, I know that if the diameter of a circle is the hypotenuse of a triangle then that triangle is a right triangle. Does this imply that the hypotenuse of any right triangle inscribed within a circle must be the diameter?

If this is not the case then I'm at a loss on how to solve this problem.

Second question, I have searched around but cannot find solutions to this book is there a place to find the solutions.
 
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Velcroe said:
I know that if the diameter of a circle is the hypotenuse of a triangle then that triangle is a right triangle. Does this imply that the hypotenuse of any right triangle inscribed within a circle must be the diameter?
Yes, it must be the diameter.
 
Velcroe said:
I am reading Gelfand's Trigonometry. In one of the questions he asks: "We know from geometry that a circle may be drawn through the three sides of any triangle. Find the radius of such a circle if the sides of the triangle are 6,8, and 10."

My first question is, I know that if the diameter of a circle is the hypotenuse of a triangle then that triangle is a right triangle. Does this imply that the hypotenuse of any right triangle inscribed within a circle must be the diameter?

If this is not the case then I'm at a loss on how to solve this problem.

Second question, I have searched around but cannot find solutions to this book is there a place to find the solutions.
Unfortunately I cannot answer your last question. The answer to the first, however, is yes. Imagine you have the hypotenuse of a right triangle in a circle and it is not the diameter. Then for the third point to be on the circle you get either a longer side which cannot be true or an angle which cannot be right which cannot be true either.
 
fresh_42 said:
Unfortunately I cannot answer your last question. The answer to the first, however, is yes. Imagine you have the hypotenuse of a right triangle in a circle and it is not the diameter. Then for the third point to be on the circle you get either a longer side which cannot be true or an angle which cannot be right which cannot be true either.

That makes sense, so the answer to Gelfand question quoted above would just be 5. Seems like the question is too easy which is why I asked my question in the first place. Well thank you for your response.
 
Velcroe said:
"We know from geometry that a circle may be drawn through the three sides of any triangle.
I think the author means a circle inscribed in a triangle, instead of the opposite. He said "sides", not "corners".
Velcroe said:
I have searched around but cannot find solutions to this book is there a place to find the solutions
If assuming the circle inscribed in a triangle is correct, then will this animation be helpful?
 
Actually my mistake in quoting the question. It actually states"... may be drawn the the three vertices of any triangle". Sorry about that don't know how I mistyped that. Fixed my original question.
 

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