Using proportions, it is found that the seismic activity density for this state is of 0.0059 earthquakes per square mile.
A proportion is a fraction of a total amount, and the measures are related using a rule of three. Due to this, relations between variables, either direct or inverse proportional, can be built to find the desired measures in the problem.
In this problem, the density is the proportion given by the number of earthquakes divided by the area, hence:
424/71,300 = 0.0059 earthquakes per square mile.
More can be learned about proportions at https://brainly.com/question/24372153
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