There is no specific rule about how many sentences a brief paragraph should have. The length can vary depending on the writing style, the purpose of the paragraph, and the overall structure of the text. However, a brief paragraph typically consists of 3 to 5 sentences. This allows the writer to convey a specific idea or supporting point without overwhelming the reader with excessive information.
A paragraph functions as a unit of thought and develops a single main idea. Whether it contains three or five sentences is a matter of how much detail and explanation the writer chooses to provide to support the main idea. The key is to maintain coherence and ensure that all the sentences relate to the paragraph's central argument or topic.