Let x represent the horizontal displacement of the top of the escalator from its bottom. The geometry of the problem and the Pythagorean theorem tell you
x² + 4.89² + 9.09² = 16.0²
x² = 149.4598
x ≈ 12.22 . . . meters
Then the tangent of the angle of interest is
tan(α) = (4.89 m)/(12.22 m)
α = arctan(4.89/12.22) ≈ 21.8°
The escalator is inclined 21.8° above the horizontal.
x² + 4.89² + 9.09² = 16.0²
x² = 149.4598
x ≈ 12.22 . . . meters
Then the tangent of the angle of interest is
tan(α) = (4.89 m)/(12.22 m)
α = arctan(4.89/12.22) ≈ 21.8°
The escalator is inclined 21.8° above the horizontal.