Hello guys, I’m Yuya and I major in mathematics. Do you know the definition of a triangle?
[A triangle is a closed figure with three straight lines]
It is a very famous definition all over the world. This picture shows that the definition is clearly correct.
However, I have an another theory. I’ll show you a counter-example. Look at the next picture.
If I make a triangle on the spherical surface, I could draw one that has more than 180 degrees. It is an interesting issue. I would be happy if this topic made you interested in maths. Thank you for reading.
Yuya Yamaguchi, Intermediate B