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In the book: The Elements Euclid defined 5 postulates:

1) A straight line segment can be drawn joining any two points.

2) Any straight line segment can be extended indefinitely in a straight line

3) Given any straight line segment, a circle can be drawn having the segment as radius and one endpoint as center.

4) All right angles are congruent.

5) If two lines are drawn which intersect a third in such a way that the sum of the inner angles on one side is less than two right angles, then the two lines inevitably must intersect each other on that side if extended far enough.

This postulate is equivalent to what is known as the parallel postulate.

can someone please explain to me how :

anything in that video breaks any of the 5 postulates of Euclidean geometry?

What makes it non-Euclidean geometry?

the first example is a tunnel that is really long from the outside but it's actually really short on the inside.

Which of the 5 postulates does this break?

definitely not 1, 2, or 3 unless I can crazy

maybe 4 by I am not sure

and unless I missed something, I thought postulate 5 unprovable.

1) A straight line segment can be drawn joining any two points.

2) Any straight line segment can be extended indefinitely in a straight line

3) Given any straight line segment, a circle can be drawn having the segment as radius and one endpoint as center.

4) All right angles are congruent.

5) If two lines are drawn which intersect a third in such a way that the sum of the inner angles on one side is less than two right angles, then the two lines inevitably must intersect each other on that side if extended far enough.

This postulate is equivalent to what is known as the parallel postulate.

can someone please explain to me how :

anything in that video breaks any of the 5 postulates of Euclidean geometry?

What makes it non-Euclidean geometry?

the first example is a tunnel that is really long from the outside but it's actually really short on the inside.

Which of the 5 postulates does this break?

definitely not 1, 2, or 3 unless I can crazy

maybe 4 by I am not sure

and unless I missed something, I thought postulate 5 unprovable.

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