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EEJ MAIN Aptitude QUESTION #10952
Question 1
A staircase has 12 steps, each 18 cm high and 28 cm wide (tread). What is the slope angle of the staircase? (Use \(\tan^{-1}(0.643) \approx 33°\)
  • \(32°\
  • \(33°\✔️
  • \(37°\
  • \(45°\
Correct Answer Explanation

Slope angle \(\theta = \tan^{-1}\left(\dfrac{\text{rise}}{\text{run}}\right) = \tan^{-1}\left(\dfrac{18}{28}\right) = \tan^{-1}(0.643) \approx 33°\

In architectural design, comfortable stair angles range from 25° to 40°. The ideal is around 30°–35°.

This is why building codes specify maximum riser heights (typically 190 mm) and minimum tread depths (typically 250 mm) — to keep the angle in a safe, comfortable range.