# Diédrico System: Distance from a point to a line

We can define the distance from a point P to a line r as the smallest of the distances from the point P to the infinite points on the line r. To determine this distance must obtain the line perpendicular to the line r from the point P and get their point of intersection I. The distance d from P to R is the minimum distance from this point to the line r.

This problem can have two different approaches to determining the solution sought.

# Diédrico System: Distance from a point to a plane

We can define the distance from a point P to a α as the smallest of the distances from the point P up to the infinite points of the plane α. To determine this distance we get the straight perpendicular to the plane α from the point P and I get your point of intersection. The distance from P to I will be the minimum distance to the plane α.

# Geometría proyectiva: Intersection of straight and tapered

Projective definition of the conical allowed to start solve classical problems of identification of new elements of the conical (new points and tangents in them), and find the intersection with a line or a tangent from an external point. These problems can be solved by various more or less complex methods and conceptually more or less laborious paths.

We will now see how to determine the two possible intersection points of a line with a taper defined by five points.

# Intersections in outlook: straight and cuboids

One of the classic problems of representation systems is to find the intersection of two elements, such as determining the intersection point between a line and a plane. Topological nature are problems in which the concepts of belonging prevail.

The problems are based on topological relationships are independent projection type in which they are.

# Representation systems : Incidence (Intersections) [ Descriptive geometry ]

Incidence problems trying to identify common elements of two geometric figures; can be defined as special cases of belonging.

Starting from the line and plane elements, We can apply the concepts of duality to analyze the possible problems that may occur.