Which statement correctly defines the total run of a stairway?

Which statement correctly defines the total run of a stairway?

• A. the sum of the tread run
• B. the total rise divided by run
• C. the sum of the risers
• D. the total number of risers

Answer: (A)

Total run is the horizontal distance of the stairway, found by adding up the depth of each tread (the run of each step). Each tread contributes a horizontal amount, and summing all those gives the overall horizontal projection from start to finish. The total rise sums the vertical increments of each step, not the horizontal distance, so it’s not about the run. Likewise, the ratio of total rise to run would describe slope, not distance, and counting risers is just a count, not a distance. So the best definition is the sum of the tread runs.

Total run is the horizontal distance of the stairway, found by adding up the depth of each tread (the run of each step). Each tread contributes a horizontal amount, and summing all those gives the overall horizontal projection from start to finish. The total rise sums the vertical increments of each step, not the horizontal distance, so it’s not about the run. Likewise, the ratio of total rise to run would describe slope, not distance, and counting risers is just a count, not a distance. So the best definition is the sum of the tread runs.