二次函数问题中,经常会遇到求一类不规则三角形的面积问题,这类问题如果按照常规的方法求解,往往比较复杂,但是如果我们能够通过作三角形的“铅垂高”来求其面积,通常要简便很多.一、定义如图1,过△ABC的三个顶点分别作出与水平线垂直的三条直线,外侧两条直线之间的距离叫△ABC的“水平宽”(图中的a),中间的这条直线在△ABC内部的线段长度 Quadratic function problems, often encounter a class of irregular triangular area problem, such problems if the conventional method of solving is often more complicated, but if we can make a triangle by the “plumb height” to Find its area, usually a lot easier.A definition of Figure 1, too △ ABC of the three vertices were made with the vertical line of the three straight lines, the distance between the two outer lines called △ ABC "horizontal width (A in the figure), the length of the line in the middle of this line in △ ABC