In Math, a line does not have any thickness. It is a mathematical concept.
Technically no, since its meant to be a one dimensional object (meaning that it can be technically described by one numerical value). But then, a one dimensional object has zero thickness, therefore it would be invisible due to it infinitely small thickness. So a line by definition has no thickness, but all true lines are invisible.
A mathemetical line segment does not exist physically for it only has length and no thickness
In typesetting, the thickness of a line is called its weight and is measured in points.
A line or a plane.
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weight
True
A point has no length, width, or thickness. A line has infinite length but no width or thickness. A plane has infinite length and width but no thickness.
a line or line-segment
None. A line is a 1-dimensional object and so has no thickness. An atom, no matter how small, has a finite thickness and so cannot be IN a line.
Line weight refers to the thickness or heaviness of a line in a design or drawing. It can help to create emphasis, hierarchy, and contrast in artwork, as well as define shapes and add visual interest. Varying line weight can also convey different moods or styles in a piece.
point
A line has infinite length, no width, no thickness, and no endpoints.