次切距

例句：

1. 1. The engineer calculated the distance between two points on the circle using the radius and the circumference.
   工程师使用半径和周长计算圆上两点之间的距离。
2. 2. The carpenter measured the length of the beam with a tape measure and marked the sub-chords for cutting.
   木匠用卷尺测量梁的长度，并在需要切割的地方做了标记。
3. 3. The scientist used a microscope to observe the microscopic structures of the sample, identifying sub-chords and sub-points.
   科学家使用显微镜观察样本的微观结构，识别出次切线和次切点。