Can the sum of angles of a planar triangle be greater than 180?

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SUMMARY

The sum of the angles of a planar triangle is always exactly 180 degrees. This is a definitive property of Euclidean geometry, which applies to flat surfaces. In contrast, on a spherical surface, the sum of the angles can exceed 180 degrees, with the excess being proportional to the area of the triangle. Therefore, the claim that the sum can be greater or lesser than 180 degrees is only applicable in non-planar geometries.

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  • Concept of angle measurement in degrees
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hermy
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Can the sum of angles of a planar triangle be greater than 180??

hii

i read somewhere that the sum of the angles of a triangle is always a little bit greater than or lesser than 180 degrees? how true is that?

thank you
 
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Welcome to PF!

Hi hermy! Welcome to PF! :smile:
hermy said:
i read somewhere that the sum of the angles of a triangle is always a little bit greater than or lesser than 180 degrees? how true is that?

It's true on the Earth's surface …

on a sphere, the sum of the angles minus 180º is proportional to the area of the triangle …

but it's not true on a plane: the sum is always exactly 180º. :smile:
 

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