1. ## Questions about triangles and lines

My first question, can a triangle have three angles, 0-180-0, and appear as a line segment with a point in the middle having no altitude?

Also, can a single dot on a piece of paper represent an infinite straight line in aspect to the dot being 3-d, extending through the paper?

My first question, can a triangle have three angles, 0-180-0, and appear as a line segment with a point in the middle having no altitude?

Also, can a single dot on a piece of paper represent an infinite straight line in aspect to the dot being 3-d, extending through the paper?
up to me you are right in both
but if the angles are allowed to be $\displaystyle 0$ in your triangle definition.

My first question, can a triangle have three angles, 0-180-0, and appear as a line segment with a point in the middle having no altitude?

Also, can a single dot on a piece of paper represent an infinite straight line in aspect to the dot being 3-d, extending through the paper?
Deriving from both, such dot can also be a triangle.