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Subject: "Pythagoras theory"     Previous Topic | Next Topic
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Conferences The CTK Exchange College math Topic #378
Reading Topic #378
Jodi
Member since Aug-12-03
 Aug-11-03, 11:48 PM (EST)
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"Pythagoras theory"
 
   Hi there I just dropped by to ask if you can tell me please:

Can you use Pythagoras theory to create a triangle with a perfect right angle?

ie I want to measure ab at say, 2 metres, then bc at say 3 metres, then for instance find the distance ac to create a perfect right angle.

You help's much appreciated

Jodi


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  Subject     Author     Message Date     ID  
  RE: Pythagoras theory Jodi Aug-12-03 1
  RE: Pythagoras theory Vladimir Aug-12-03 2
  RE: Pythagoras theory Graham C Aug-19-03 3
     RE: Pythagoras theory Graham C Jan-22-04 5
         RE: Pythagoras theory alexbadmin Jan-22-04 6
  RE: Pythagoras theory NIH Jan-21-04 4
     RE%3A Pythagoras theory erika Feb-11-07 7
         RE: RE%3A Pythagoras theory alexbadmin Feb-11-07 8

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Jodi
Member since Aug-12-03
 Aug-12-03, 09:11 AM (EST)
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1. "RE: Pythagoras theory"
In response to message #0
 
   Hi guys,

You helped me to work it out without even answering me!

it's 3metres2 x 4metres2 = 5metres2

Thanks!

Jodi


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Vladimir
Member since Jun-22-03
 Aug-12-03, 09:11 AM (EST)
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2. "RE: Pythagoras theory"
In response to message #0
 
   For practical applications, AB = 2m and BC = 3m would be inconvenient, for CA = Ö(4 + 9) = Ö13m. But you can easily generate plenty of integer Pythagorean triples such that a2 + b2 = c2. Certain Pythagorean triples were used in ancient times in construction work long before Pythagoras discovered his theorem. For example, the ancient Egyptians knew the Pythagorean triple (3, 4, 5) and the ancient Indians (from India) the Pythagorean triple (5, 12, 13). I imagine that they made a circular rope with 3 + 4 + 5 = 12 resp. or 5 + 12 + 13 = 30 equidistant marks labeled 1, 2, ..., 12 resp. 30 and then they stretched the rope at the marks 3, 7, and 12 resp. 5, 17, and 30.


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Graham C
Member since Feb-5-03
 Aug-19-03, 11:24 PM (EST)
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3. "RE: Pythagoras theory"
In response to message #0
 
   This reminds me of an old problem (I'm thinking 40 years ago) which some people may not be familiar with.

You have an inexhaustible supply of matches, which can be linked together at their ends, but not rigidly - i.e. they can wiggle around.

Your task is to construct a rigid right-angle that cannot be deformed (other than by breaking the matches).

What is the minimum number of matches you need?


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Graham C
Member since Feb-5-03
 Jan-22-04, 07:45 AM (EST)
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5. "RE: Pythagoras theory"
In response to message #3
 
   Has this problem really been buried for six months?

Should I post an answer?


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alexbadmin
Charter Member
1954 posts		 Jan-22-04, 07:48 AM (EST)
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6. "RE: Pythagoras theory"
In response to message #5
 
   Please do. Thank you.


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NIH
Member since Jan-21-04
 Jan-21-04, 09:02 AM (EST)
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4. "RE: Pythagoras theory"
In response to message #0
 
   Strictly speaking, you can't use Pythagoras' Theorem to do this. What you need is the converse of Pythagoras' Theorem, which states that, in a triangle with sides a, b, c such that a^2 + b^2 = c^2, the angle opposite c (the hypotenuse) is a right angle.

Nick


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erika
guest
 Feb-11-07, 07:22 PM (EST)
 
7. "RE%3A Pythagoras theory"
In response to message #4
 
   can u tell me what is pythagoras theory!!!!!!!!!!!!!!!!!!!!!!!


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alexbadmin
Charter Member
1954 posts		 Feb-11-07, 07:24 PM (EST)
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8. "RE: RE%3A Pythagoras theory"
In response to message #7
 
   Check

https://www.cut-the-knot.org/pythagoras/ or
https://www.google.com/search?hl=en&q=pythagoras+theory


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