I Math Myth: The sum of all angles in a triangle is 180°

AI Thread Summary
The sum of angles in a triangle on a spherical surface exceeds 180 degrees, challenging the traditional understanding taught in schools. This phenomenon varies based on the triangle's size, making flat triangles the exception rather than the rule. The discussion highlights a common misconception about geometry in real-world applications. Participants express surprise at this revelation, indicating it was not commonly taught. Understanding this concept is crucial for grasping the complexities of geometry beyond flat surfaces.
Messages
19,781
Reaction score
10,734
From @fresh_42's Insight
https://www.physicsforums.com/insights/10-math-things-we-all-learnt-wrong-at-school/

Please discuss!

We all live on a globe, a giant ball. The angles of a triangle on this ball add up to a number greater than ##180°##.

Kugeldreieck.png


And the amount by which the sum extends ##180°## isn't even constant. It depends on the size of the triangle. The flat triangle with angle-sum ##180°## is the exception, not the norm. The real world is crooked.
 
Last edited by a moderator:
Mathematics news on Phys.org
This is something I never knew in school! Has anyone else heard of this before?
 
Suppose ,instead of the usual x,y coordinate system with an I basis vector along the x -axis and a corresponding j basis vector along the y-axis we instead have a different pair of basis vectors ,call them e and f along their respective axes. I have seen that this is an important subject in maths My question is what physical applications does such a model apply to? I am asking here because I have devoted quite a lot of time in the past to understanding convectors and the dual...
Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...

Similar threads

Replies
3
Views
2K
Replies
1
Views
2K
Replies
4
Views
1K
Replies
142
Views
9K
Replies
5
Views
2K
Replies
14
Views
2K
Back
Top