perquadrat

例句：

1. 1. The perquadrat is used to measure the length of a line.
   测地线用于测量一条线的长度。
2. 2.The geodesic triangle is a special type of triangle that can be used to find the shortest distance between two points on a sphere.
   测地三角形是一种特殊的三角形，可以用来找到球面上两点之间的最短距离。
3. 3. The meridian is the line of longitude that passes through the center of the Earth.
   本初子午线是地球中心穿过的经线。