在平面直角坐标系中求三角形的面积是很常见的题型,而对于三边都不与坐标轴平行或重合的三角形面积,一般采用“割补法”间接求面积,大多数的学生都喜欢采用补成矩形(或直角梯形)等来进行面积的加减,而笔者遇到这类问题时常采用的一种求面积的方法是用平行于y轴的直线去分割. It is common to find the area of ​​a triangle in a Cartesian coordinate system. For a triangle area where the three sides are not parallel to or coincident with the coordinate axis, the area is usually calculated by the method of " Like the use of make-up rectangular (or right-angle trapezoidal) and so on for the addition and subtraction of the area, and I encountered such problems often use a method of seeking area is parallel to the y-axis to a straight line to split.