The knowledge points of mathematical geometry are summarized as 1, and there is only one straight line after two points.
2. The line segment between two points is the shortest.
3. The complementary angles of the same angle or equal angle are equal.
5. There is one and only one straight line perpendicular to the known straight line.
6. Of all the line segments connecting a point outside the straight line with points on the straight line, the vertical line segment is the shortest.
7. Parallelism axiom: After passing a point outside a straight line, there is one and only one straight line parallel to it.
8. If two straight lines are parallel to the third straight line, the two straight lines are also parallel to each other.
9. The same angle is equal, and two straight lines are parallel.
10, internal dislocation angles are equal, and two straight lines are parallel.
1 1, the inner angles on the same side are complementary, and the two straight lines are parallel.
12, two straight lines are parallel and have the same angle.
13, two straight lines are parallel and the internal dislocation angles are equal.
14. Two straight lines are parallel and complementary.
Theorem: The sum of two sides of a triangle is greater than the third side.
16, inference: the difference between two sides of a triangle is smaller than the third side.
17, the theorem of the sum of interior angles of a triangle, the sum of three interior angles of a triangle is equal to 180.
18, inference 1: The two acute angles of a right triangle are complementary.
19, Inference 2: One outer angle of a triangle is equal to the sum of two inner angles that are not adjacent to it.
20. Inference 3: An outer angle of a triangle is greater than any inner angle that is not adjacent to it.
Junior high school geometry formula theorem: rectangle 1, rectangle property theorem 1 All four corners of a rectangle are right angles.
2. Theorem of Rectangular Properties: Two diagonal lines of a rectangle are equal.
3. Rectangular Decision Theorem 1 A quadrilateral with three right angles is a rectangle.
4. Rectangular Decision Theorem 2 A parallelogram with equal diagonals is a rectangle.
Junior high school geometry formula: rhombus 1, rhombus property theorem 1 all four sides of the rhombus are equal.
2. Theorem of Diamond Properties 2 Diagonal lines of diamonds are perpendicular to each other, and each diagonal line bisects a set of diagonal lines.
3, diamond area = half of the diagonal product, that is, S=(a×b)÷2.
4. Diamond Decision Theorem 1 A quadrilateral with four equilateral sides is a diamond.
5. Diamond Decision Theorem 2 Parallelograms whose diagonals are perpendicular to each other are diamonds.
Junior high school mathematics mind map
The above is my summary of the knowledge points of mathematical geometry. Thank you for reading.