CREATE TABLE table_9180 ("Official Name" TEXT, "Status" TEXT, "Area km 2" FLOAT, "Population" FLOAT, "Census Ranking" TEXT)

What is the population when the area km2 is 173.4?
SELECT "Population" FROM table_9180 WHERE "Area km 2" = '173.4'
SELECT "Population" FROM "table_9180" WHERE "Area km 2" = '173.4'