Probability obtuse triangle - simple one

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Homework Help Overview

The discussion revolves around the probability of forming an obtuse triangle given two sides with exponentially distributed lengths and an angle between them that is uniformly distributed over [0, 2π]. Participants are exploring why the probability of obtaining an obtuse triangle is greater than 0.5.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants are questioning the reasoning behind the probability being greater than 0.5 rather than exactly 0.5. There is an exploration of the conditions under which a triangle can be obtuse, particularly considering the distribution of angles.

Discussion Status

Some participants have suggested that the obtuse angle's probability may be influenced by the lengths of the sides and the nature of the other two angles in the triangle. There is an acknowledgment of the need to consider the overall configuration of the triangle, but no consensus has been reached on the exact reasoning.

Contextual Notes

Participants are grappling with the implications of the uniform distribution of the angle and how it relates to the obtuse condition, as well as the relationship between the angles in a triangle summing to 180 degrees.

wuid
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Homework Statement



The two sides lengths of a triangle is exponentially distributed. (not so important for my question)

The angle between the sides is uniformly distributed [0,2∏]

c) explain why the probability to get obtuse triangle is greater then 0.5

The Attempt at a Solution



i don't understand why it is grater then 0.5 and not exactly 0.5...
 
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wuid said:

Homework Statement



The two sides lengths of a triangle is exponentially distributed. (not so important for my question)

The angle between the sides is uniformly distributed [0,2∏]

c) explain why the probability to get obtuse triangle is greater then 0.5

The Attempt at a Solution



i don't understand why it is grater then 0.5 and not exactly 0.5...

Hi wuid! :smile:

Looks like the question is the probability to get any obtuse angle in the triangle (also considering the other 2 angles)...
 
i am missing something... to get obtuse triangle is that the probability of the angle to be between [∏/2,3∏/2] so what i thought is : what is the probability that θ is within the II or III quarter of the plane so it is P(II)+P(III) = 0.25 + 0.25 = 0.5.

where i am wrong ?
 
What about the other 2 angles of the triangle?

Suppose your angle is acute, but one side is very long while the other side is very short.
What kind of triangle would you have?
 
obtuse triangle :)
so without calculation, can i say that the probability is greater than 0.5, because that i get obtuse angle with probability 0.5 but i need to add a measure of probability that the other two angles would sum up with the first on to 180 degrees ? gives that the triangle is obtuse.
 
Yep! :smile:
 
I never see the all picture...
thank you !
 
You're welcome! :wink:
 

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