Final answer:
If a ramp has a rise of more than 6 inches or a horizontal projection of more than 72 inches, it should have a landing platform or a safety railing.
Step-by-step explanation:
In the context of ramps, a rise refers to the vertical distance from the bottom of the ramp to its highest point, while a horizontal projection refers to the distance from the bottom of the ramp to the point where it ends horizontally. According to the question, if a ramp has a rise of more than 6 inches or a horizontal projection of more than 72 inches, it should have a landing platform or a safety railing at the higher end to ensure safety.