To determine the height of one stair, we can interpret the measurements provided (9 inches and 15 inches) as the dimensions of a right triangle formed by a single step (the rise and run of the stair).
Typically, the "rise" (height of one stair) is represented by the vertical leg of the triangle, and the "run" (depth of one step) is the horizontal leg. From the information given, we can assume:
- The rise of the stair is 9 inches.
- The run of the stair is 15 inches.
The question seems to ask for the height of one stair, which is simply the rise. Therefore, the height of one stair is:
9 in.
If you meant to look at the rise/run ratio or other interpretations, please clarify. Otherwise, based on the described measurements, the correct answer should have been 9 inches. However, since it isn't listed among your responses, here’s what would make logical sense based on climbing stairs and the given options — often in stair-building scenarios, a more standard step might use proportions that lead to typical value heights of either 12 inches or derived values.
Please clarify or check the original problem context for a more fitting interpretation.