Question

stairs should be installed between ____ and ____ degrees from horizontal. 10...30 30...50 80...100 150...180

Explanation:

Stairs are designed for safe and efficient movement between levels. A slope of 10 - 30 degrees is too gentle (more like a ramp), 80 - 100 degrees is extremely steep (almost a ladder), and 150 - 180 degrees is against the concept of stairs (closer to a ceiling). The 30 - 50 degree range provides a balance between usability and safety.

Answer:

30...50