前面三节,我们主要讲了两个内容:三角形的构成及三角形的内角和.前一个内容说的是三角形的三条边之间的关系:对于任何一个三角形,任意两条边长度的和大于第三边;任意两条边长度的差小于第三边.以上结论中的第2条是前一条的推论,这就是三角形构成法则.要想使某三条线段能成为一 In the previous three quarters, we mainly talked about two things: the composition of triangles and the internal angles of triangles. The former one talks about the relationship between the three sides of a triangle: for any triangle, the sum of the lengths of any two sides is greater than the third Edge; The difference between the lengths of any two sides is less than the third side. Article 2 in the above conclusion is the inference of the previous one. This is the triangle formation rule. To make a certain three line segments become one