CREATE TABLE table_64105 ("School" TEXT, "Location" TEXT, "Mascot" TEXT, "Size" FLOAT, "IHSAA Class" TEXT, "# / County" TEXT, "Year Joined" FLOAT, "Previous Conference" TEXT)

What's the year that Hagerstown joined?
SELECT "Year Joined" FROM table_64105 WHERE "School" = 'hagerstown'
SELECT "Year Joined" FROM "table_64105" WHERE "School" = 'hagerstown'