Non coplanar lines.
Coplanar lines.
They can be, but not necessarily. If two lines in the same plane never intersect, they are parallel. Though, two lines can exist in the same plane without being parallel. Ie, two lines that intersect at a 90 degree angle are perpendicular. Most lines in a plane aren't parallel.
parallel lines If they are not on the same plane and never intersect they are skew
parallel lines :)
Theorem: If two lines intersect, then exactly one plane contains both lines. So, when two or more lines intersect at one point, they lie exactly in the same plane. When two or more lines intersect at one point, their point of intersection satisfies all equations of those lines. In other words, the equations of these lines have the same solution, which is the point of intersection.
Coplanar lines.
Two lines that do not intersect on the same plane are Parallel lines.
Points on the same plane are coplanar lines.
Two coplanar (in the same plane) lines that don't meet are parallel.
They can be, but not necessarily. If two lines in the same plane never intersect, they are parallel. Though, two lines can exist in the same plane without being parallel. Ie, two lines that intersect at a 90 degree angle are perpendicular. Most lines in a plane aren't parallel.
If the two lines lie in the same plane, and they do not intersect, then they are parallel. If they are not in the same plane, and do not intersect, then they are called skew lines.
the same line
Two parallel lines. Such lines have the same slope.
parallel lines If they are not on the same plane and never intersect they are skew
parallel lines :)
Two lines can lie in one plane. For example, parallel lines are lines that intersect and lie in the same plane.
Theorem: If two lines intersect, then exactly one plane contains both lines. So, when two or more lines intersect at one point, they lie exactly in the same plane. When two or more lines intersect at one point, their point of intersection satisfies all equations of those lines. In other words, the equations of these lines have the same solution, which is the point of intersection.