三角形是最简单、最重要的几何图形,在数学解题中,若能根据题目的结构特点,大胆展开联想,巧妙构造三角形,不但能顺利找到题目的突破,且能使许多复杂问题简单化,本文以四种题型为例举例说明,愿与大家共赏． The triangle is the simplest and most important geometric figure. In the mathematical problem solving, if we can boldly expand the association according to the structural characteristics of the topic and construct the triangle skillfully, not only can we find the breakthrough of the problem smoothly, but also it can simplify many complex problems. This article uses four questions as examples to illustrate and is willing to share with everyone.