You have to design a wheelchair-accessible ramp next to a set of steps leading up to a building. The height from the ground to the top of the stairs is 8.9 ft. Based on ADA codes, the height to base ratio must be 1:15 or less.

What is the minimum ramp slope length that you need?

*note, please thoroughly explain how you got your answer, I need to study from this and know how to solve it.