Using the slope concept, it is found that the angle from Matilda to the top of the blast was of 38.66º.
The slope is given by the vertical change divided by the horizontal change, and it's also the tangent of the angle of depression.
In this problem, the vertical change is of 100 ft, while the horizontal change is of 125 ft, hence:
[tex]\tan{\alpha} = \frac{100}{125}[/tex]
[tex]\alpha = \arctan{\left(\frac{100}{125}\right)}[/tex]
[tex]\alpha = 38.66^\circ[/tex]
The angle from Matilda to the top of the blast was of 38.66º.
More can be learned about the slope concept at https://brainly.com/question/18090623