quadrilateral directional distance relay

例句：

1. 1. The quadrilateral is the shape of a four-sided figure.
   这个四边形是四面体的外形。
2. 2. The quadrilateral is used to describe the shape of a rectangle.
   这个四边形用来描述矩形的形状。
3. 3. The quadrilateral is a basic geometric shape in mathematics.
   这个四边形是数学中的基本几何形状。