Two lines orthogonal to a third line are parallel?

Yes, two lines that are orthogonal (perpendicular) to a third line are indeed parallel to each other.

This is because if a line is orthogonal to another line, it means that it forms a right angle (90 degrees) with that line. If two lines are both orthogonal to the same line, they are both forming a right angle with that line. Therefore, they must be parallel to each other, because parallel lines are lines in the same plane that do not intersect and the angle between parallel lines is always 180 degrees or 0 degree, which is consistent with the fact that the sum of the angles in a triangle is 180 degrees (the third line forms a triangle with the two parallel lines).