CREATE TABLE table_73312 ("Regional County Municipality  ( RCM ) " TEXT, "Population Canada 2011 Census" FLOAT, "Land Area" TEXT, "Density  ( pop. per km2 ) " TEXT, "Seat of RCM" TEXT)

What is the land area of the RCM having a density of 21.1?
SELECT "Land Area" FROM table_73312 WHERE "Density (pop. per km2)" = '21.1'
SELECT "Land Area" FROM "table_73312" WHERE "Density (pop. per km2)" = '21.1'