A stair must rise 126 in. floor-to-floor. Using a maximum riser height of 7 in., what riser count is required?
Correct Answer
C) 18 risers
Divide total rise by the maximum riser: 126/7 = 18, so 18 risers satisfy the 7 in. maximum. Other choices exceed the maximum riser height or add unnecessary risers.
Why This Is the Correct Answer
Divide total rise by the maximum riser: 126/7 = 18, so 18 risers satisfy the 7 in. maximum. Other choices exceed the maximum riser height or add unnecessary risers.
Why the Other Options Are Wrong
Option A: 17 risers
stair layout, choice a: 17 risers counts a different spacing, panel, or repeated member quantity.
Option B: 19 risers
stair layout, choice c: 19 risers counts a different spacing, panel, or repeated member quantity.
Option D: 20 risers
stair layout, choice d: 20 risers counts a different spacing, panel, or repeated member quantity.
Memory Technique
Remember stair layout as "base, adjustment, final unit"; the last unit should read 18 risers.
Reference Hint
Open International Building Code 2021 or 2024; use IBC stair riser layout using 1011.5.2 maximum riser height to confirm that Divide total rise by the maximum riser: 126/7 = 18, so 18 risers satisfy the 7 in.
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