Stair Construction: Calculating the Number of Risers and Unit Rise
How do you determine the number of risers required and their unit rise when building a stair with a total rise of 7' - 7"?
a) 14 risers with a unit rise of 6 inches each
b) 13 risers with a unit rise of 7 inches each
c) 15 risers with a unit rise of 6 inches each
d) 12 risers with a unit rise of 8 inches each
Final answer: Option (a)
Answer:
The correct answer for a stair with a total rise of 7 feet 7 inches is 14 risers with a unit rise of 6 inches each.
Stair construction requires some mathematical computations. When building a stair with a total rise of 7 feet and 7 inches, you need to determine the number of risers required and their unit rise.
Firstly, let's convert the total rise into inches. 7 feet is equal to 84 inches. Adding the additional 7 inches gives a total rise of 91 inches.
Now, dividing the total rise by the number of risers can give the unit rise. If we consider the provided options:
a) 14 risers with a unit rise of 6 inches each
b) 13 risers with a unit rise of 7 inches each
c) 15 risers with a unit rise of 6 inches each
d) 12 risers with a unit rise of 8 inches each
Only option a) 14 risers with a unit rise of 6 inches each fits the total rise of 91 inches correctly (14 risers * 6 inches/riser = 84 inches), leaving 7 inches for the landing. Therefore, the correct answer is a - 14 risers with a unit rise of 6 inches each.
Understanding these calculations and choosing the correct number of risers and unit rise is crucial for safe and accurate stair construction.