SAT Question 873d2838: Ratios Rates Proportional Relationships And Units answer and explanation with Desmos solution

It's given that the population density of Cedar County is $230$ people per square mile and the county has a population of $85,100$ people. Based on the population density, it follows that the area of Cedar County is $\left(85,100\text{people}\right)\left(\frac{1\text{square mile}}{230\text{people}}\right)$, or $370$ square miles.