Cylinder: cylinder, prism

Cone: Cone, Pyramid

ball

front, left, top

point

Wire

noodle

body

Point movement to form a line, line movement to form a surface, surface movement to form a body

①Static definition: The figure composed of two rays with common endpoints is called an angle. This common endpoint is the vertex of the angle. These two rays are the two sides of the angle and can be extended wirelessly.

②Dynamic definition: The figure formed by a ray rotating around its endpoint to another position is called an angle. The ray at the initial position is called the initial side of the angle, and the ray at the ending position is called the final side of the angle.

Metrics

Overlay method

1 circumferential angle = 360°, 1 straight angle = 180°, 1 right angle = 90°

1 circumferential angle = 2 square angles = 4 right angles

A ray starting from the vertex of an angle and dividing the angle into two equal angles is called the bisector of the angle.

If the sum of two angles is 90°, then the two angles are supplementary angles.

Supplementary angles of same (equal) angles are equal

If the sum of two angles is 180°, then the two angles are supplementary angles.

Supplementary angles of same (equal) angles are equal

It is customary to write south or north first and east or west last.

Two points determine a straight line

Between two points, the line segment is the shortest

Straight line: A line that can extend infinitely to both ends is called a straight line

Ray: A point on a straight line and the part beside this point are called rays, and this point is called the endpoint of the ray.

Line segment: Two points on a straight line and the middle part are called line segments, and these two points are called the endpoints of the line segment. The length of the line segment connecting two points is called the distance between the two points.

Both rays and line segments are part of a straight line

Rule and compass drawing

Long and short comparison

The point that divides a line segment into two equal segments is called the midpoint of the line segment.

The length of the line segment connecting two points