Truncation formula: the sum and difference of line segment and one and a half times, the extension and shortening can be tested, and the inequality of line segment and difference is moved to the same triangle.

Note: When encountering the relationship of sum, difference and half times of line segments, you can try truncation to make up for each other. Truncation refers to intercepting one segment of a long line segment equal to one of the other two segments, and then proving that the rest is equal to the other segment; Complement refers to extending a short line segment, the extended part is equal to another short line segment, and then proving that the new line segment is equal to the long line segment.

The common conditions in the topic are isosceles triangle (that is, two sides are equal) or bisector (that is, two angles are equal). After learning from each other's strengths and connecting some points, the final conclusion is drawn.

Truncation: a vertical line passing through a point as the long side; Intercept a line segment that is the same as one short side on the long side, and then prove that the remaining line segment is equal to the other short side.

Complementarity: extend the short side; Connect two short sides together by rotation, etc. Intercept complementation: a method of adding auxiliary lines to junior high school mathematical geometry problems, and also an idea of making geometry problems difficult and easy. Truncation is to cut a line into two parts, and complementarity is to extend on one side to make it equal to a desired side.

Related information:

Truncation method can intercept a short segment from a long segment and convert it into proof that the remaining segment is equal to another short segment. Or extending a short line segment to another short line segment and transforming it into a proof that a combined line segment is equal to a long line segment. This is the so-called truncation method, that is, to learn from each other's strengths.

When a geometry problem can't be proved directly, sometimes we can use the method of learning from others' shortcomings as an auxiliary line, so as to make our thinking suddenly clear and solve the problem.

Skills:

Skills: nouns refer to ingenious skills in literature, craft and sports. Such as "conversation skills"; Or refers to the technical movement. Such as "Skills Competition". Five strokes of phonetic interpretation: RFAG skills: that is, the clever use of basic methods.