projective cone

例句：

1. 1. The projective cone is a mathematical concept that describes the shape of a cone when viewed from above.
   投影锥体是描述圆锥从上方观看时形状的数学概念。
2. 2. In geometry, the projective cone is used to define the volume and surface area of a solid object.
   在几何学中，投影锥被用来定义固体物体的体积和表面积。
3. 3.The projective cone is an important tool in studying the properties of materials, as it allows for the calculation of the internal angles and lengths of the cone's sides.
   投影锥是研究材料性质的重要工具，因为它允许计算锥体的边的内部角度和长度。