proportional action coefficient

例句：

1. 1.The proportion of students who failed the exam was proportional to their grades.
   考试不及格的学生比例与他们的分数成正比。
2. 2. The company's profitability is closely related to its cost structure, which is a proportional action coefficient.
   公司的盈利能力与其成本结构密切相关，这是一个比例系数。
3. 3. The ratio of male to female students in this class is proportional to the number of students in the class.
   这个班级男生和女生的比例与班级人数成正比。