What is the minimum text height required for signage to be legible from a distance of 90 feet?

To determine the minimum text height required for signage to be legible from a distance of 90 feet, it's important to consider the general guidelines established for signage readability. A common rule of thumb is that text height increases in proportion to the distance from which it needs to be read.

For effective visibility, it's often estimated that for every 10 feet of distance, the text should be approximately 1 inch tall. Using this guideline, at a distance of 90 feet, the minimum text height would need to be about 9 inches to ensure legibility. However, since the choices provided list a minimum option of 4 inches, selecting that option indicates a misunderstanding of proper visibility standards for signage.

Among the options, the choice of 4 inches is indeed the minimum presented, but it doesn't tie in with the clarity needed for visibility at 90 feet. The correct insight would lean toward considering either 6 or 8 inches as more closely aligned with visibility standards that advocate for larger heights for effectiveness at longer distances. Thus, while 4 inches is a listed choice, it does not meet the criteria for legibility from the given distance.

This means signs with text smaller than what is suggested by guidelines would not be effectively legible for most viewers