What is Pythagorean theorem: Definition and 46 Discussions

In mathematics, the Pythagorean theorem, or Pythagoras's theorem, is a fundamental relation in Euclidean geometry among the three sides of a right triangle. It states that the area of the square whose side is the hypotenuse (the side opposite the right angle) is equal to the sum of the areas of the squares on the other two sides. This theorem can be written as an equation relating the lengths of the sides a, b and c, often called the Pythagorean equation:





a

2


+

b

2


=

c

2


,


{\displaystyle a^{2}+b^{2}=c^{2},}
where c represents the length of the hypotenuse and a and b the lengths of the triangle's other two sides. The theorem, whose history is the subject of much debate, is named for the Greek thinker Pythagoras, born around 570 BC.
The theorem has been proven numerous times by many different methods—possibly the most for any mathematical theorem. The proofs are diverse, including both geometric proofs and algebraic proofs, with some dating back thousands of years.
The theorem can be generalized in various ways: to higher-dimensional spaces, to spaces that are not Euclidean, to objects that are not right triangles, and to objects that are not triangles at all but n-dimensional solids. The Pythagorean theorem has attracted interest outside mathematics as a symbol of mathematical abstruseness, mystique, or intellectual power; popular references in literature, plays, musicals, songs, stamps, and cartoons abound.

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  1. C

    B Question about Morin's time dilation explanation

    Hello everyone, I'm reading Morins book which I like, and I feel I kind of understand the part on time dilation, however I'm a little confused by the geometry of the Pythagorian theorem when applied to velocities. On the moving clock he shows the velocity of light on the diagonal it traces...
  2. Slipjoints

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  3. B

    I Dirac Matrices and the Pythagorean Theorem

    I understand that momentum, rest mass and energy can be put on the sides of a right triangle such that the Pythagorean Theorem suggests E^2=p^2+m^2. I understand that the Dirac equation says E=aypy+axpx+azpz+Bm and that when we square both sides the momentum and mass terms square while the cross...
  4. A

    MHB Pythagorean Theorem: Unexpected Finding

    Hello, today i was playing around with the pythagorean theorem and found out something that i can't really explaing or atleast explain it with probably a false answer. So i was putting every possible combination with the max digit of 10. For example 1^2+1^2=\sqrt{2}, 1^2+2^2=\sqrt{5}...
  5. M

    MHB Converse of Pythagorean Theorem

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  6. Kirito123

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  7. Hatesmondays

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  8. caffeinemachine

    MHB A Fact I Observed While Looking at the Proof of the Pythagorean Theorem.

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  9. C

    How accurate is pythagorean theorem?

    I'm just wondering: How accurate is the pythagaroen theorem? To what exact decimal point is the calculated length of the hypotenus in a triangle 100% corect when using pythagarean theorem? It must not be 100% accurate to an infinite descimal point since it's called a "Theorem"
  10. A

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  11. Ismael Nunez

    Is the Pythagorean Theorem Applied to Determine the Length of AB?

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  12. L

    How to find angle after applying Pythagorean Theorem?

    Hello, so I have a question that states (these aren't the actual measurements but they are around about the same, I can't remember the exact numbers so I made these up, this way I could apply the same to the actual numbers) an object being 4km above me, 1.4km to the north of me, and 2km to the...
  13. P

    MHB Consequences of the Pythagorean Theorem

    Hello! I have a homework for tomorrow. The question is: What are the consequences of the Pythagorean theorem?? On Wikipedia, they mixed the consequences and the uses of the theorem in one paragraph: 5.1 Pythagorean triples 5.2 Incommensurable lengths 5.3 Complex numbers 5.4...
  14. T

    Pythagorean theorem based on cross product.

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  15. B

    Disproving Pythagorean Theorem

    Ever since I was in grade school I have been fascinated with the idea that the Pythagorean theorem, or any other universally respected theorem, could be wrong. When I was younger I found a little proof I made to disprove it, and I came across it in an old notebook of mine. Now after taking...
  16. S

    Proving the Pythagorean Theorem

    I am wondering what it means to "prove" the Pythagorean Theorem in modern mathematics. Most real analysis begins with the following definition of the n-dimensional Euclidean metric: ##d(x,y) = |y-x| = \sqrt{\sum\limits_{i=0}^{n} (y_i-x_i)^2}## This would seem to directly imply the...
  17. S

    Pendulum motion and pythagorean theorem

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  18. W

    Disproof to the Pythagorean Theorem?

    Ok I realize the Pythagorean Theorem is correct. I completely get that very basic concept this is just a question I have. On a right triangle a^2 + b^2 = c^2 with c being the hypotenuse. But if instead of the hypotenuse connecting the two legs you had a jagged line that went halfway up...
  19. M

    I found out new proof of Pythagorean theorem , how can I publish it ?

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  20. Q

    Is this equivalent to the Pythagorean Theorem?

    So I was reading up on the Pythagoreans, and I came across this page: http://www.math.ufl.edu/~rcrew/texts/pythagoras.html . I don't see the reasoning behind this statement. I tried some simple algebra on this statement and couldn't get Pythag to fall out of it. Can someone figure out a...
  21. C

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  22. P

    Spherical Pythagorean theorem - finding length of longer side

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  23. M

    Deriving Invariant Distance in Space Time: Pythagorean Theorem

    Why in deriving invariant distance in space time we use Pythagorean Theorem with a negative sign?
  24. E

    Proof of the Pythagorean theorem using Dimensional analysis

    hello, in the Wikipedia page for http://en.wikipedia.org/wiki/Dimensional_analysis#Proof_of_the_Pythagorean_theorem" how do we know that area = "largest edge2 • f (angle1, angle2)"? Isn't it just as reasonable to say something like area= (largest edge/40000)2 • f (angle1, angle2) ?
  25. G

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  26. F

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  27. N

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    I just learned the proof for the Pythagorean theorem.. my mind was blown! =D Simply amazing.
  28. C

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  29. L

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  30. L

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  31. Char. Limit

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  32. K

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  33. D

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  34. P

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  35. M

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  36. R

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  37. U

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  38. S

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  39. S

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  40. E

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  41. U

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  42. L

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  43. J

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  44. D

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  45. O

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  46. S

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