An important factor in a person's ability to comfortably read text on a displayed image is the height of the characters. If the farthest viewer cannot easily read the text, then the presenter may have difficulty communicating information. The 150 multiplier, also known as the 150 Rule, provides a guideline for determining the maximum distance the viewer can sit and still read the text of a known height.
There is a direct relationship between the height of the text and the distance of the viewer. As text height increases, so does the distance. As text height decreases, so does the distance.
