一、高的意义。从三角形一个顶点向它的对边作一条垂线,垂线顶点和垂足之间的线段叫作三角形这条边上的高。如下图中AD就是三角形ABC底边BC上的高。三角形的高是一条线段。由于三角形有三条边,可分别作底边,所以三角形有三条高。 First, the high meaning. Make a vertical line from one vertex of the triangle to its opposite edge. The line between the vertex of the perpendicular and the foot of the foot is called the height above the edge of the triangle. AD is the height of BC on the bottom of triangle ABC as shown below. The height of the triangle is a line segment. As the triangle has three sides, respectively, for the bottom, so the triangle has three high.