Final answer:
County X could be represented by a rectangular or square shape with an area of 600 square miles.
Step-by-step explanation:
The shape of County X can be approximated as a rectangle or a square. Since the population density is given as 250 people per square mile and the total population is 150,000, we can calculate the area of County X by dividing the population by the population density. Area = Population / Population Density = 150,000 / 250 = 600 square miles. Therefore, County X could be represented by a rectangular or square shape with an area of 600 square miles.