Final answer:
The approximate population density in the city in 2010 was 393.1 residents per square kilometer.
Step-by-step explanation:
To find the population density, we need to divide the population by the area. In this case, the population is 65,870 residents and the area is 167.7 square kilometers. So, the population density is:
65,870 residents / 167.7 square kilometers = 393.1 residents per square kilometer
Therefore, the approximate population density in 2010 was 393.1 residents per square kilometer.