When there is no common point between two straight lines on a plane, two planes in space and a straight line and a plane in space, it is said to be parallel. As shown in the figure, the straight line AB is parallel to the straight line CD and marked as AB∑CD, and the parallel lines do not intersect at any distance.

Rotation is the circular motion of an object around a point or an axis. For example, the earth rotates around the earth's axis and also around the sun. Xinhua dictionary (version 1 1) [1]? And Modern Chinese Dictionary (7th Edition) [2]? Pronunciation is xuá n Zhu; But the world turns to Zhu) In mathematics, rotation is a graphic movement.

Axisymmetry means that if a plane figure is folded along a straight line, the parts on both sides of the straight line can overlap each other, then this figure is called a figure with reflective symmetry, and this straight line is called the axis of symmetry.

Parallelism, rotation and axial symmetry are the basic types of graphic motion.

Extended data

Lines and surfaces can also be parallel, surfaces and surfaces can also be parallel (just as planes and planes can be parallel), and curves and curves can also be parallel.

In a plane, a figure rotates an angle around a vertex in a certain direction, which is called rotation. In a plane, turning a figure around a fixed point by an angle in a certain direction is called rotation. Point o is called the center of rotation, and the rotation angle is called the rotation angle. If point P on the graph rotates into point P, then these two points are called corresponding points of this rotation.

Two symmetric graphs are congruent. If two graphs are symmetrical, then the symmetry axis is the median vertical line connecting the symmetrical points.

Reference source

Baidu Encyclopedia-Axisymmetric

Baidu encyclopedia-parallel imports

Baidu encyclopedia-rotate