在平面向量的复习中,很多学生对向量与三角形的“四心”这类问题不知从何入手,究其原因在于学生对三角形的“四心”定义的理解不深刻,对向量条件转化不娴熟,下面就通常出现的几类问题例析如下.1重心:三角形三条中线的交点,三角形顶点到该点距离与该点到对边中点距离之比为2∶1 In the review of the plane vector, many students do not know where to start the problem of the “four hearts” of the vector and the triangle. The reason is that students do not deeply understand the definition of the “four hearts” of the triangle, and they are not familiar with the transformation of the vector conditions. In the following, several types of problems that commonly arise are illustrated as follows. 1 Center of gravity: The intersection of the triangle’s three centerlines. The ratio of the distance from the vertex of the triangle to the point and the distance from the point to the midpoint of the opposite side is 2:1.