Question

A staircase is being constructed in a new house as displayed on the right. Each tread is 18 cm and each riser is 10cm. Determine the angle of inclination of the stairs.

Answer 1

29.1°

Explanation:

Given that :

Riser, AB, Opposite = 10 cm

Thread, = AC, Adjacent = 18 cm

Angle of inclination, θ

Using trigonometry :

Tan θ = opposite / Adjacent = AB / AC

Tan θ = 10 / 18

θ = tan^-1(10/18)

θ = 29.055

Hence, angle of inclination is 29.1° (1 decimal place)