Let's start with this.
Obviously, if someone rages in a classroom, most of those present will go into shock.
Including the teacher.
Thus, even if a teacher has been trained in handling violence in a classroom, his or her access to these responses will in all likelihood be limited.
The thing to remember here is the idea, "that which you resist persists.
" In other words, any attempt to push the rage back in the direction of the student will only result in the student raging more.
Including psychological attempts to logically calm the student down.
At the same time, simply waiting for this student's rage to pass will not be a stable nor supportive response either.
Moreover, if a student has become so unbalanced as to be raging in a classroom, the teacher must do something.
The thing to keep in mind here is, blame is like gasoline poured on a fire, where anger is the fire.
Blame the student for being angry and you exacerbate the student's rage.
In addition, as you know, blame can take many forms.
Thus, while yelling back is one form of blame, patronizing an angry person with logic is yet another.
Doing either will just make the situation worse.
All this said, the thing which makes your question difficult to answer is you do not mention what the student is mad at.
Thus, I have no way of knowing what kinds of specific responses might be helpful.
As such, I can only offer vague and general advice.
What I am saying is, the crux of the matter here is determining the nature of this student's rage.
Not the psychological "cause," mind you; that is merely yet another form of blame.
Rather, determining the simple, straight forward focus of this student's anger.
For instance, is he or she angry at something which was said during this class? Or did this student walk into class already fuming and angry? Does this student have a history of angry outbursts? Or is this rage something which is totally out of character for this student? Is this student involved in some kind of an adversarial relationship within this class? The leader of the class rebels, perhaps? Is she a loner who feels she is fighting the whole world? Was this student recently involved in a romantic breakup? Is he the son of an active alcoholic? Whatever the case, knowing this student's personal character is the key to knowing how to respond.
And while being shocked by an angry outburst normally puts most people on the defensive, blaming the person for having this outburst will only make things worse.
Finally, there is the question of the teacher's internal emotional response.
Is this teacher afraid of physical violence? Then the thing to do is to immediately do something to seek help.
Having two adults in a classroom in this kind of situation can help.
And make the rest of the class feel safer.
On the other hand, if the teacher makes no attempt to help other than to call for help, then she or he risks losing the respect of the whole class.
In addition, if the teacher has a history of having been wounded of violence, then she or he should later seek professional counseling at the next possible time.
Why? Because while students raging in a classroom is never normal, yet to be faced fears regarding violent students will have a profoundly negative impact this teacher's ability to teach.
Including that the whole class will subconsciously feel this fear and will be profoundly affected.
Bottom line.
The teacher needs to know how to handle these situations.
But he or she need not feel the entire solution should come form within themselves.
Get help.