Direct in space

A straight line in space is one of the main figures in geometry. It consists of an infinite number of abstract objects that lack volume, area, length, and any other characteristics. These zero-dimensional objects also serve as fundamental figures in geometry and are called points.

The straight line in space is similar to the one that is carried out on the existing plane. With the help of the imagination, two points should be marked. Between them, as well as beyond their limits to infinity with the help of a ruler, a line is drawn. This is the straight line in space. On this line, you can designate a segment or a point. These actions are similar to the same actions performed on a plane.

In geometry, there are axioms that concern the definition of a line. These include the following statements:

1. Through two marked points one can draw only one single line.

2. There are cases when two separate points of a line are in a certain plane. Then we can say that all zero-dimensional objects of the line are in it.

Thanks to these axioms, it becomes obvious that the line in space lies entirely in a certain plane.

In geometry, one more case is considered. It arises in those situations where a straight line in space appears as a consequence of the intersection of two different planes. The statement is true: if two different planes have at least one common point, then they have a common straight line. On this line all common zero-dimensional objects of these geometric figures lie .

The mutual arrangement of straight lines in space can have different options. In individual cases, they may coincide. That is, in this version, the lines have an infinite set of common points.

Lines in space can have one common point. In this variant, the data lines are in a certain plane located in three-dimensional space. This case leads to an understanding of the angle arising between the lines.

To be located in space, lines can also be parallel. In this situation, they are in the same plane and do not intersect throughout their entire length.
On a line, as well as on a line parallel to it, a nonzero vector will be its directing. This geometric concept is often used in solving various problems. Using the vector, you can determine the direction of a straight line.
Lines can also be interbreeding. In this case, they are located in different planes. This arrangement leads to a geometric concept of the angle that lies between the crossed straight lines. Particular attention is drawn to the cases of perpendicular arrangement of lines in three-dimensional space. In such embodiments, the angle between them is a value equal to ninety degrees.

You can specify a straight line in space using various methods. To do this, knowledge of axioms will help. Proceeding from the fact that only one straight line can pass through two points marked in space, we can map it by drawing a line through the planned zero-dimensional objects.

If it is necessary to construct a geometric figure in a coordinate system of a rectangular form, which is located in three-dimensional space, then an equation is made. When specifying a straight line, it is necessary to rely on the coordinates of its two points, which must be known.

When constructing the necessary line, we can use the parallelism theorem. In this case, through a certain point that does not belong to our straight line, we can always construct a geometric figure, all zero-dimensional objects of which will belong only to it.

The plane and the line in space can also be perpendicular. To construct a line in this case, a geometric figure is drawn. In this case, the angle of intersection of such a straight line and the plane is 90 degrees.