vertex of a conic

例句：

1. 1. The mountain's vertex is visible from the top of the peak.
   这座山的顶点从山顶上可见。
2. 2.The vertex of a cone is its highest point.
   圆锥的顶点是它的最高点。
3. 3. The vertex of a triangle is the point where the sides meet.
   三角形的顶点是三条边相交的地方。