1. complementary angle: if the sum of two angles is a right angle, then these two angles are called complementary angles, that is, one of them is the complementary angle of the other.

(1) The complementary angle is for two angles, which is only related to the degree of the angle and has nothing to do with the position of the angle (deep understanding);

(2) Although it is called "complementary angle", it does not have to appear in pairs. For example, in a complex figure, there may be many complementary angles.

(3) A complementary example: in a right triangle, two acute angles are complementary; The angle can be calculated accordingly.

2. Complementary angle: If the sum of two angles is a right angle, then these two angles are complementary angles, that is to say, one of them is the complementary angle of the other.

(1) complementary angle is also aimed at two angles, which is related to the size of the angle and has nothing to do with the position (deep understanding);

(3) Although it is called "complementary angle", it does not have to appear in pairs. For example, in a complex figure, there may be many complementary angles.

(3) Examples that must be supplemented: For a triangle, its outer angle is complementary to its adjacent inner angle; The angle can be calculated accordingly.

3. Diagonal angle: Like this, the straight line AB and the straight line CD intersect at O, and ∠ 1 and ∠2 have a common vertex, and their two sides are opposite extension lines, so these two angles are called diagonal angles.

The essential characteristics of (1) antipodal angle are: (a) the two angles have a common vertex; (b) Both sides of the two corners are extension lines opposite to each other;

(2) Enantiomers always appear in pairs, and they are enantiomers;

(3) An angle has only one antipodal angle.

4. The same side of the Angle, Angle and Angle:

(1) When identifying the congruence angle, pay attention to the two characters in the position, and cut in the same direction as the two lines on the same side of the third line.

(2) When identifying the internal angle, it depends on whether the two angles are between two straight lines and on both sides of the line.

(3) When identifying the internal angle on the same side, it depends on whether the two angles are on the same side of the cutting line or between the two cutting lines.

5. Ruler painting: Only drawing rulers and compasses without drawing scale is called ruler painting.

That should be it. I chose it from my class notes.