Considering the vertex of the quadratic function, it is found that:
A robot traveling along the surface of the curved pit reaches a minimum depth of -22.25 feet.
<h3>What is the vertex of a quadratic equation?</h3>
A quadratic equation is modeled by:

The vertex is given by:

In which:
Considering the coefficient a, we have that:
- If a < 0, the vertex is a maximum point.
- If a > 0, the vertex is a minimum point.
In this problem, the function is given by:
y = 0.75x² - 13.5x + 57.75.
Which means that the coefficients are a = 0.75 > 0, b = -13.5, c = 57.75.
Thus, the minimum value is given by:

Thus:
A robot traveling along the surface of the curved pit reaches a minimum depth of -22.25 feet.
More can be learned about the vertex of a quadratic function at brainly.com/question/24737967