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# Do parellel lines ever meet? watch

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1. (Original post by Pzyko)
I triangle on a sphere is a stupid concept because any idiot can see (except, possibly, you) that the lines making up the triangle aren't straight. I can draw a triangle on a flat piece of paper that doesn't have straight edges but has angles that add up to more than 180 degrees. It just wouldn't be a triangle.

So I repeat: he probably didn't understand any of it.
triangle - "geometric figure with 3 sides and 3 angles."

Since when do the lines have to be straight? And don't call me an idiot, my Maths teacher told me this and she has more knowledge than you as regards to Maths.
2. (Original post by Invisible)
triangle - "geometric figure with 3 sides and 3 angles."

Since when do the lines have to be straight? And don't call me an idiot, my Maths teacher told me this and she has more knowledge than you as regards to Maths.
My maths teacher told me that he hated the whole concept of spherical triangles and I'm sure that he has more knowledge than both you, I and your maths teacher. I will therefore continue to hold my beliefs that you are an idiot and that the concept of spherical triangles is stupid.
3. You can draw three-sided shapes on curved surfaces: they do meet the technical definition of a triangle, but the shape will only have 180° on a flat plane.

To be fair though, the more I learn about physics, the less I understand about it. Every single time you explain something, more inconsistencies pop up. Is light a particle or a wave? How can it be both?
4. (Original post by Squishy)
You can draw three-sided shapes on curved surfaces: they do meet the technical definition of a triangle
I can still think that it's a stupid concept.
5. (Original post by Pzyko)
My maths teacher told me that he hated the whole concept of spherical triangles and I'm sure that he has more knowledge than both you, I and your maths teacher. I will therefore continue to hold my beliefs that you are an idiot and that the concept of spherical triangles is stupid.
Your teacher thinking the idea is stupid isn't a decent answer. I'm going by the definition of a triangle.

"Geometric shape with 3 sides and 3 angles." - It doesn't specify that the lines must be straight.

Clearly the person who made the theorem only considered straight lined triangles as we do.

"he has more knowledge than both you, I and your maths teacher." - Not enough to give any definitive answer though, and the fact that he doesn't appreciate the definition of a triangle doesn't enhance his argument any more. i.e.) "it's just stupid".
6. (Original post by Pzyko)
I can still think that it's a stupid concept.
Why though? If you drew a triangle on the ground, it would be very slightly a "spherical triangle", because the surface of the Earth is not flat. In fact, Euclidean geometry is not realistic at all. You can even have a triangle on the surface of a tennis ball that has three right angles...I think it's cool.
7. (Original post by Invisible)
Your teacher thinking the idea is stupid isn't a decent answer. I'm going by the definition of a triangle.

"Geometric shape with 3 sides and 3 angles." - It doesn't specify that the lines must be straight.

Clearly the person who made the theorem only considered straight lined triangles as we do.

"he has more knowledge than both you, I and your maths teacher." - Not enough to give any definitive answer though, and the fact that he doesn't appreciate the definition of a triangle doesn't enhance his argument any more. i.e.) "it's just stupid".
I didn't say that lines had to be straight, I just said I found the concept of a triangle or any polygon that doesn't have straight lines as being stupid. I'm sure you'd agree if I drew a curved triangle on a plane. You're arguing against a point that wasn't made.
8. (Original post by Squishy)
Why though? If you drew a triangle on the ground, it would be very slightly a "spherical triangle", because the surface of the Earth is not flat. In fact, Euclidean geometry is not realistic at all. You can even have a triangle on the surface of a tennis ball that has three right angles...I think it's cool.
Curved surface of the Earth is negligible. Drawing triangles on tennis balls is stupid.
9. (Original post by Pzyko)
has more knowledge than both you, I and your maths teacher.
surely thats 3 people? maybe you cant count?
10. (Original post by visesh)
surely thats 3 people? maybe you cant count?
Maybe it was a grammatical slip up like your omission of apostrophes and capital letters?
11. (Original post by Pzyko)
Maybe it was a grammatical slip up like your omission of apostrophes and capital letters?
gud point. but seeing as this is a maths forum...
12. (Original post by Pzyko)
Curved surface of the Earth is negligible. Drawing triangles on tennis balls is stupid.
Curved traingles can still meet the definition of a triangle.
13. (Original post by Pzyko)
Curved surface of the Earth is negligible. Drawing triangles on tennis balls is stupid.
You seem very against the idea of "flat" shapes on curved surfaces or curved shapes on flat ones. The curvature of the Earth's surface is negligible, but it doesn't mean we can't study it. Gauss did, and he was a brilliant mathematician. Also, understanding the curvature of space-time is a very important part of modern physics.

Come on, if you're a mathematician, have a little imagination.
14. (Original post by Invisible)
Curved traingles can still meet the definition of a triangle.
Are you arguing against my opinion that curved triangles are a load of *******s?
15. (Original post by Pzyko)
Are you arguing against my opinion that curved triangles are a load of *******s?
You're saying that triangles are bollox?
16. (Original post by Squishy)
You seem very against the idea of "flat" shapes on curved surfaces or curved shapes on flat ones. The curvature of the Earth's surface is negligible, but it doesn't mean we can't study it. Gauss did, and he was a brilliant mathematician. Also, understanding the curvature of space-time is a very important part of modern physics.

Come on, if you're a mathematician, have a little imagination.
I'll consider it when I need to.
17. (Original post by Invisible)
You're saying that triangles are bollox?
No.
18. (Original post by Pzyko)
Are you arguing against my opinion that curved triangles are a load of *******s?
They do look like mis-shapen *******s.
19. (Original post by Pzyko)
No.
Well clarify yourself. If you only accept straight sided triangles, then at least say so. Don't say "triangles" as this includes straight lined triangles drawn on a non-flat plane, hence making them curved.

You can argue a case, but the definition will stand irregardless.
20. (Original post by Invisible)
Don't say "triangles" as this includes straight lined triangles drawn on a non-flat plane
The point is that a line that follows a non-flat plane isn't straight other than with respect to the plane.

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