When 82.74 is the area in kilometers squared what is the pop.density (per km2)?
CREATE TABLE "table1_29289372_1" (
  "city_municipality" text,
  "population_2010" real,
  "area_km" text,
  "pop_density_per_km" text,
  "income_classification" text
);
SELECT "pop_density_per_km" FROM "table1_29289372_1" WHERE "area_km"='82.74';