The line plane angle ranges from 0 to 90. A point passing through a straight line that is not parallel to the plane is regarded as the vertical line of the plane, and the intersection of this straight line and the plane is an included angle with the connecting line of the original straight line. The general method to solve the plane angle of a line is to determine two vectors first, and then find the cosine of the included angle between the two vectors, and pay attention to determining the relationship between the included angles of vectors.
A point on a straight line that is not parallel to the plane is regarded as the vertical line of the plane, and the straight line between the intersection of this vertical line and the plane and the intersection of the original straight line and the plane consists of the original straight line (the complementary angle of the included angle between this vertical line and the original straight line).
meaning
Usually, an object consists of several points, lines and faces. A polygon can be identified as an edge. Traditionally, how many polygons a three-dimensional model has is called how many faces it has, that is, how many faces the model has.
Points, lines and surfaces are the basic elements used to construct three-dimensional objects. Usually, an object consists of several points, lines and faces. The planes that define most three-dimensional objects are called faces-just like cutting diamonds-or polygons. Polygons can be regular or irregular.
Many 3D shapes generated by 3D computer software consist of polygons. Simple geometric shapes can be defined by dozens of polygons; Objects that need a lot of details, such as tea cups, need hundreds of polygons to form details. Complex objects, such as a detailed mannequin, may need thousands of polygons.
Models of natural phenomena may require millions of polygons. A polygon can be identified as an edge. Traditionally, how many polygons a three-dimensional model has is called how many faces it has, that is, how many faces the model has.
Father of geometry
Euclid once defined an angle as the relative inclination of two non-parallel straight lines on a plane. Proclos thinks that angle may be a trait, a quantifiable quantity, or a relationship. Oldham thinks that an angle is a deviation from a straight line, and Cabus of Antioch thinks that an angle is a space between two intersecting straight lines. Euclid thinks that an angle is a relationship, but his definitions of right angle, acute angle or obtuse angle are quantitative.