Hey there!
There are three main types of appeal in a sentence. These are also known as modes of persuasion. They are logos, ethos, and pathos.
Logos is appealing to someone based on logic, facts, and statistics.
Ethos is appealing to someone based on one's credibility or experience when giving a statement. An example of using ethos could be quoting a psychologist's opinion on what causes depression in teens.
Pathos is appealing to someone based on emotions and feelings, usually in a sentimental or dramatic story.
In our situation, we see that the teacher uses a number: 20%. This makes it a statistic, so the appeal used is logos. This statistic can be used to back up that many people are calling in sick and that the problem needs to be solved.
Have a wonderful day!