How can a journalist determine the type of audience?

A journalist can determine what type their audience is by either personally getting to know them, or by their form of writing, if they write mature writing such as a documentary about wars or ancient history, their audience is most likely older and mature, and if they were to write documentaries about animals, their audience is most likely younger children. All in all, it depends on what they report or write about.

Through a survey.

Explanation:

Journalists can determine the type of audience through a survey.